Chapter Text
Alistair woke hard.
Not slowly. Not peacefully. One instant darkness, the next full awareness with every instinct already screaming that something was wrong.
He sat upright before his eyes properly focused, breath sharp in his lungs.
Wrong room.
That landed first.
Not danger. Not attack. Just wrongness.
The bedroom was dark except for the faint glow of city light leaking around blinds. Modern shapes. Clean lines. A low electronic hum somewhere nearby. Nothing military about it. No familiar furniture. No books stacked beside the bed. No reading glasses abandoned half-open.
And he—
He froze.
His hands looked wrong.
Younger.
The skin across them was smooth, strong tendons under healthy flesh instead of age spots and thinning veins. He flexed automatically and felt strength answer at once, effortless in a way his body had not obeyed in years.
His heart started beating harder.
Slowly, carefully, he swung his legs off the bed and stood.
No ache in the knees.
No stiffness in the hip.
No old injury pulling at damp-weather joints.
Thirty years gone in an instant.
"…What the devil…"
His voice stopped him too.
Too young.
The room tilted unpleasantly for a moment.
Alistair steadied himself against the bedside table and forced himself to breathe.
Assess.
Panic later.
Military instinct slid into place automatically, old as bone.
The flat was silent. No sign of intrusion. No movement. No obvious threat.
He checked the bedside table first. Phone — modern, unhelpful. A watch he didn't recognise. Wallet.
The wallet mattered.
He opened it immediately.
UNIT identification card. Colonel Alistair Gordon Lethbridge-Stewart.
The photograph made his stomach drop.
Thirty-five at most. Dark hair without grey. Hard jaw. Eyes too old for the face staring back at him.
Himself.
The card trembled slightly between his fingers before he mastered the reaction.
His eyes narrowed.
Impossible. Temporal displacement? Psychic attack? Toymaker nonsense? Time Lord interference?
Dead?
No answer came.
He opened the wallet further. Bank cards. Receipts. A folded shopping list written in hurried block capitals — milk, tea, Kate's lunch things, printer ink.
Then a photograph slid partly free from behind one of the inner sleeves.
Small. Creased at the edges from handling.
A blonde girl grinning gap-toothed at the camera. School uniform slightly crooked. Blue eyes sparkling with mischief. Across the bottom, in childish handwriting: Dad stop carrying this one it's embarrassing.
Alistair stopped breathing.
Kate.
Not grown. Not standing in UNIT command. Not a woman.
A child.
His hand closed around the wallet.
He moved through the flat quickly but quietly, every instinct narrowing toward a single objective.
Find her.
The second bedroom door stood slightly open. Soft light from the corridor edged across posters, discarded school clothes, books stacked precariously beside the bed.
And there—
Kate.
Eleven years old. Blonde hair everywhere across the pillow. One arm flung above her head. Fast asleep under a duvet half-covered in stars and half-covered in what appeared to be printed dinosaurs.
A science textbook lay open face-down beside her.
Alistair stood in the doorway and simply stared.
This was worse than impossible.
This was personal.
Carefully, almost against his own will, he stepped closer. There were traces of the adult Kate around the edges already — the stubborn chin, the intensity even in sleep, one hand curled around a screwdriver she'd apparently fallen asleep holding.
But she was little.
God.
She was little.
Something in his chest twisted so sharply he had to sit on the edge of the bed before it showed on his face.
The mattress shifted slightly beneath his weight. Kate made a soft annoyed noise and burrowed deeper into the pillow.
"…Dad?"
Sleep-roughened. Barely awake.
Alistair couldn't answer immediately. Because she'd said it so naturally.
Dad.
Not Brigadier. Not Sir. Not Commander.
Dad.
Kate cracked one eye open blearily. "You're looming."
His throat tightened. "…Am I?"
"Yes." She squinted at him. "Why are you awake?"
Excellent question.
"I'm not certain."
"Hm."
Apparently deciding this was sufficient explanation, she shut her eyes again almost immediately. Then, half-asleep: "You look weird."
That nearly made him laugh.
Nearly.
Instead he looked down at this impossible second chance sleeping in front of him and felt something dangerously close to fear settle quietly under his ribs. Because whatever had happened — whatever universe this was — Kate existed here. And he already knew with terrible certainty that he would burn this entire reality to the ground before he let anything happen to her.
Kate fell asleep again almost immediately. Children did that — one moment conscious enough to accuse him of looming, the next gone entirely, sprawled diagonally across the bed as though gravity affected her differently than everyone else.
Alistair stayed where he was for another few seconds. Just watching her breathe.
Real. Warm. Alive. Eleven.
Then the Brigadier asserted itself over the father again.
Information first.
He eased himself silently off the mattress, tugged the duvet properly back over her shoulder by reflex, and left the room.
The flat felt less alien now that he knew Kate was inside it. Not safe. Not understandable. But inhabited.
Traces of a life were everywhere — school paperwork clipped to the fridge beneath UNIT schedules, trainers abandoned by the door, a mug in the sink with dried tea at the bottom, a half-finished model satellite spread across the dining table beside Kate's maths homework.
Lived in.
His life, apparently. Or someone's.
The computer sat in the corner of the sitting room on a proper desk — multiple screens, docking stations, external drives, secure hardware. UNIT issue.
Alistair sat cautiously. The screen woke instantly under his touch. Facial recognition accepted him.
That was unsettling.
Three seconds later a desktop appeared. He stared — not because of the technology, though that alone was enough to make his head ache. The unsettling part was the organisation. The filing structure made sense to him. Not consciously at first. Instinctively.
Operational folders separated by theatre. Threat-level colour coding. Archived intelligence cross-referenced by region and species designation.
Efficient. Military. Him. Or close enough to be uncomfortable.
He opened the personnel records first.
UNIT — Unified Intelligence Taskforce. Not United Nations anymore. Political restructuring after several public alien incidents. Increased autonomy. International funding branches. Civilian partnerships. Scientific divisions large enough to rival governments.
Modern UNIT had become enormous. And heavily bureaucratic.
His mouth flattened.
Too many contractors. Too much privatisation. Far too many committees.
But operationally effective. Response times improved. Integrated surveillance. Rapid deployment. Orbital monitoring platforms.
Whoever this Colonel Lethbridge-Stewart had been, he was competent.
Alistair felt an odd flicker of relief at that. Then discomfort immediately after, because the realisation carried a darker implication beneath it.
This wasn't random. The similarities were too precise.
He opened the service record.
Colonel Alistair Gordon Lethbridge-Stewart. Born 1990.
His eyes narrowed immediately.
No. Wrong. Not his life — not merely younger. Different. Different childhood. Different timeline. Different wars. Different promotions. Divorced 2022. One dependent child. Current commanding officer, UK Division UNIT Strategic Operations.
He leaned back slowly in the chair.
Not temporal regression then. Replacement. Parallel reality. Or something close enough that the distinction barely mattered.
The silence of the flat pressed strangely around him.
On instinct he opened another folder. Personal.
Kate's school records appeared first. He found himself reading them with embarrassing intensity. Excellent mathematics. Advanced sciences. Repeated notes regarding argumentative tendencies. One teacher comment describing her as "exceptionally bright but prone to questioning instructions she considers irrational."
His mouth twitched despite himself.
Definitely his daughter, then.
There were photographs too. Kate at museums. Kate holding what appeared to be a homemade rocket. Kate missing several front teeth, proudly standing beside a science fair display.
And him. Younger. Laughing in some of them.
One photograph stopped him cold.
Kate asleep against his shoulder on a sofa while he read from a tablet balanced one-handed against his knee. Domestic. Unposed. Real.
The expression on the younger Colonel's face was not one Alistair remembered wearing often.
Contentment.
That hurt unexpectedly. Because whoever this man had been — whatever had happened to him — he had loved Kate properly. Not distantly. Not abstractly. Presently.
Alistair shut the photograph after a moment.
The ethical problem loomed larger the more he learned. Was the other man dead? Displaced? Suppressed? Watching helplessly from somewhere behind his eyes?
The thought made him feel slightly ill.
He stood abruptly and paced once across the room.
Think. He needed data points. Comparisons.
He pulled up UNIT historical records.
That was where the real disorientation began.
Some things matched — the Yeti, Auton incursions, enough familiar names and events to make his skin crawl. But altered. Shifted. The Doctor appeared in fragments only: contradictory reports, missing files, strange references buried under classification levels even he couldn't immediately access.
And Sarah Jane Smith—
Alistair stopped.
Her name sat buried inside a civilian consultation report attached to an archaeological incident in Peru. Dr. Sarah Smith. Xenoarchaeology and comparative systems specialist.
He stared at the screen for a very long moment.
Not Sarah Jane. Not a journalist. Doctor.
A pulse of recognition hit him hard enough to be almost physical anyway. His fingers moved before he consciously decided to search deeper. Photograph request pending. Civilian consultant status. Repeated conflicts with UNIT command structures. Multiple papers flagged internally as "operationally disruptive."
His mouth twitched despite himself.
Of course she was.
Then the image file finally loaded.
And for one impossible second his entire body forgot which universe it belonged to.
Alistair did not sleep again. Not properly.
By the time dawn started bleeding grey around the edges of the blinds, he had built the rough shape of the situation whether he liked it or not. Parallel universe. Alternate life. Modern UNIT. Different history wearing familiar bones.
And somehow, impossibly: Kate.
He shut the computer down just before seven when he heard movement down the corridor. A door opened. Padded footsteps.
Kate appeared wearing oversized pyjama trousers, one sock, and a faded UNIT sweatshirt that had clearly once belonged to him. She stopped when she saw him already awake.
"…Did you even go back to bed?"
"I may have become distracted."
"You're making the tea weird."
Alistair looked down automatically. He had, apparently, made tea in what this household considered the wrong mug.
Kate looked genuinely suspicious. "That's your work mug."
"I fail to see the issue."
"You hate that mug."
"…Do I?"
"Yes. You said it looks like something a management consultant would own."
Alistair looked at the mug again. It did look insufferably smug.
"…Fair."
Kate narrowed her eyes. "You're really weird today."
He hid the instinctive tension before it reached his face. Children noticed too much. "Am I?"
"You forgot it was Sunday."
That startled him enough that she immediately caught it.
"Aha."
"I merely lost track of the day."
"You checked your watch three times while making toast."
"I was assessing timing."
"You burned the toast."
"…Operational setback."
Kate snorted hard enough she nearly dropped herself into a kitchen chair laughing.
And it was wonderful. Not grandly. Not dramatically. Just wonderfully ordinary.
The Brigadier had spent so much of his life in crises that he had almost forgotten what peace felt like when it wasn't temporary. Now there was simply tea, burnt toast, Kate stealing the least-burnt pieces, weak sunlight through the kitchen window, nowhere immediately on fire.
He found himself relaxing by degrees without meaning to.
Kate shoved a grocery list across the table with all the solemnity of a military briefing. "We need cereal."
"We have cereal."
"We have your cereal."
Alistair examined the list. Several items had little stars beside them. "What do the stars signify?"
"Important."
"Chocolate biscuits are important?"
"Yes."
"Hm."
Kate leaned on her elbows watching him strangely. "You're in a good mood."
That caught him off guard. "Am I?"
"A bit."
He considered arguing the point, then decided against it.
Kate studied him another moment, blue eyes narrowed thoughtfully over the rim of her tea mug. "You've been different since yesterday."
His hand paused briefly against the handle of his cup.
Different how? But he did not ask the question aloud. Never ask questions you do not want answered.
Instead he said evenly, "People vary from day to day."
"Not like this."
Too observant already. Alistair kept his expression carefully neutral. "And what precisely have you observed?"
"You're quieter."
That surprised him. "I'm normally quiet."
"No." Kate shook her head slightly. "You're usually work quiet."
Work quiet.
God.
Children named things with terrifying precision sometimes.
"Like you're still thinking about UNIT even when you're home," Kate continued, matter-of-fact rather than accusing.
Apparently this universe's Colonel carried command around his shoulders more visibly than Alistair had realised. Or perhaps all soldiers did.
"You actually listened to me this morning," Kate added.
That landed harder than anything else had. Not because she sounded hurt. Because she sounded accustomed to it.
Alistair looked down at the tea in his hands for a long moment before speaking carefully. "I'm sorry if I've been inattentive."
Kate blinked, startled by the apology. Then suspicious. "…Okay. That's definitely weird."
Despite himself, the corner of his mouth twitched. Not because it was amusing. Because she was trying to make this easier for him without understanding why he needed her to. And somehow that made him love her a little already.
By the time they left for the supermarket, the morning had settled into something dangerously close to normal.
Kate walked beside him with easy familiarity, hands shoved into the pockets of her hoodie while she complained about school with the focused seriousness only eleven-year-olds could manage.
"Mrs. Harding says Pluto isn't a proper planet."
Alistair glanced down at her. "That debate is still ongoing, apparently."
"Well, it's stupid."
"A compelling scientific argument."
"It is." Kate frowned up at him. "You can't just decide something stops being a planet because you changed your mind."
"I believe the issue is slightly more complex than that."
"She's still wrong."
Alistair found himself almost smiling. Partly because she expected him to argue with her. Partly because he genuinely enjoyed listening to her think. And partly because a quiet, painful part of him had already begun cataloguing the day.
Just in case.
The thought arrived unwanted while they crossed the car park. You may lose this. The flat. The mornings. The shopping lists with stars beside biscuits. An eleven-year-old Kate arguing passionately about Pluto while sunlight caught in her blonde hair.
This might all vanish as suddenly as it arrived.
Alistair straightened unconsciously against the feeling. Soldiers learned very early not to cling too tightly to temporary things. That had never stopped them wanting them.
Inside the supermarket, Kate commandeered the trolley with the confidence of someone who had done this dozens of times before. "We need cereal."
"We have cereal."
"We have your cereal."
"And what precisely is wrong with my cereal?"
"It tastes like responsibility."
That nearly earned a laugh out of him. Nearly.
Instead he took the grocery list from her and examined it carefully. Proper meals. Lunch supplies. Tea. Fruit. Printer ink. A real household — not chaos, not survival. Living.
He found he liked that more than he expected.
Kate tossed pasta into the trolley while continuing her commentary about school. "Oliver says aliens definitely built the pyramids."
"Did he provide evidence?"
"He said 'it just makes sense.'"
"A weak foundation for scientific inquiry."
"That's what I said!"
People noticed him occasionally as they moved through the shop. Small pauses. Double-takes. Recognition. UNIT had become public enough here that he carried visibility in civilian spaces, and he disliked it instinctively. Too exposed.
Kate, however, seemed entirely accustomed to it. "Don't do the face," she said quietly while selecting apples.
"What face?"
"The Colonel face."
"I have no idea what you mean."
"The one that makes people think they're in trouble."
"I am not intimidating civilians in a supermarket."
"You made that man apologize for blocking the beans aisle."
"I merely looked at him."
"Exactly."
Despite himself, Alistair felt the faintest pull toward amusement.
The odd thing was how easy Kate made silence feel. Not forced. Not performative. Comfortable. They moved naturally around each other, reaching for things automatically, trading the trolley back and forth without discussion, existing inside routines the other Colonel must have built over years.
Alistair found himself studying those routines carefully. What vegetables Kate chose first. How often she checked prices before putting things in the trolley. The fact she automatically reached for his preferred tea without asking.
Evidence of a life.
His chest tightened unexpectedly at that. Because these weren't grand memories — not birthdays or crises or triumphs. This was the architecture underneath love. Accumulation. Repetition. Presence.
At some point Kate wandered briefly ahead toward the bakery section while he paused to compare two jars of pasta sauce. A small thing. Ordinary.
Yet the moment she disappeared from immediate sight, instinct snapped through him hard enough to be physical. His head came up instantly, scanning, locating exits, finding her. There — blonde ponytail near the bread shelves. Safe.
The reaction unsettled him more than he cared to admit.
Kate noticed him watching as she returned. "You know I'm not five, right?"
"I'm aware."
"You keep checking where I am."
Alistair considered denying it. Did not. "I expect that's difficult to stop."
Kate looked at him for a moment then. Really looked. Not teasing. Just thoughtful.
"…I don't mind," she said quietly.
That nearly undid him in the middle of the supermarket. So instead he picked up the nearest item off the shelf and inspected it with entirely false concentration. "Chocolate biscuits appear to have infiltrated the trolley."
Kate brightened instantly, mercifully allowing the subject to pass. "Oh good, you noticed."
"You thought I wouldn't?"
"I thought you'd pretend not to."
"…Fair."
And together they continued down the aisle beneath harsh supermarket lights, carrying on a life that belonged to another man while Alistair silently tried to memorise every second of it before the universe decided to take it away again.
The ice cream was entirely Kate's idea. Or rather, Kate's assumption — she spotted the little shop halfway back to the flat and slowed automatically beside him.
Then, clearly remembering herself, straightened again and kept walking with exaggerated dignity.
Alistair noticed anyway. Of course he did.
He followed her gaze toward the brightly painted window with its aggressively cheerful sign.
"You want ice cream."
Kate shoved her hands deeper into her hoodie pockets. "Not desperately."
"Hm."
"I mean, it's a bit cold for it."
"Mm."
"You don't have to do the mysterious noise thing. It's very annoying."
Alistair looked thoughtfully toward the shop. Then, with all the solemnity of a military decision: "I believe we can survive the meteorological conditions."
Kate's face lit instantly before she tried to suppress it. "Really?"
"I assume modern medicine has advanced sufficiently to survive frozen desserts in October."
Kate laughed properly at that, bright and effortless.
And God. That sound settled somewhere deep inside him far too quickly.
A few minutes later she sat beside him outside the shop with mint chocolate chip balanced carefully in both hands while Alistair held what appeared to be plain vanilla with the grim resignation of a man who considered most modern flavours deeply suspicious.
Kate eyed his cone critically. "You always pick the boring one."
"Vanilla is reliable."
"So are potatoes. That doesn't make them exciting."
"I'm not certain ice cream should be exciting."
"That's because you're old."
The word slipped out casually. Kate froze immediately after saying it — not frightened, just surprised by her own phrasing.
Alistair felt something twist quietly under his ribs. Because she was wrong. And somehow, impossibly, she wasn't.
Kate glanced sideways at him. "Sorry."
"No need."
"You're not actually old."
If only she knew.
He looked down at the ice cream slowly melting against the cone and found himself absurdly grateful for the cold air. It gave him a reason for the tightness in his throat.
Children measured time so strangely. To Kate, thirty-five probably did seem ancient some days — responsible, established, immovable. She had no idea she was sitting beside a man who had already lived another lifetime.
"You know," Kate said around another bite of ice cream, "you're nicer today."
That startled him enough he answered honestly before caution returned. "Am I?"
"Yeah." Not accusation. Observation.
Kate kicked lightly at the pavement with one trainer. "You actually seem like you want to be here."
The words landed softly. Far softer than if she'd meant to wound him.
Apparently the other Colonel had spent too much time half-absent — too buried under UNIT and responsibility and whatever fractures had broken his marriage apart. Alistair looked out across the street for a long moment before answering carefully. "There are worse places to be."
Kate looked pleased by that in a quiet, almost relieved way, as though some tension she'd gotten used to carrying had eased slightly without her fully understanding why.
They finished the ice cream slowly while traffic drifted past and weak autumn sunlight slid gold across the pavement. Ordinary. Completely ordinary.
Alistair found himself holding onto that with surprising desperation.
Back at the flat, Kate dumped shopping bags onto the counter and announced: "You said I could pick dinner."
"Did I?"
"Yes. Before the ice cream. Legally binding."
"I see."
Kate considered with enormous seriousness. Then: "Lasagna."
"A complex request."
"You made it last month."
Apparently the other Colonel could cook better than Alistair expected. Or perhaps Kate's standards were simply forgiving.
"Very well."
Kate brightened immediately and started unpacking ingredients with determined efficiency while Alistair rolled up his sleeves.
"You know," she said while organising vegetables with alarming authority, "you're less scary when you cook."
"I was unaware cooking altered my threat profile."
"You hum."
That stopped him entirely. "I what?"
"You hum when you're concentrating."
Alistair stared at her. Because he had. Years ago — before retirement, before loneliness settled too heavily into the bones, before silence became easier than joy.
Kate looked up from the counter, suddenly uncertain. "…You didn't know?"
For one dangerous moment emotion caught him completely off guard. This life — this impossible borrowed life — contained pieces of himself he thought had vanished decades ago. Small things. Human things. The way he cooked. The way he listened. The fact he apparently hummed absently while making dinner for his daughter on Sundays. Proof that somewhere along the line this version of Alistair Lethbridge-Stewart had managed to become something gentler than war usually allowed.
And standing in the kitchen while Kate argued about the correct amount of cheese for lasagna, the Brigadier found himself fiercely, unexpectedly grateful that he had gotten to see it at all.
Alistair woke before the alarm.
For one brief, disorienting instant he expected to find himself back in his own narrow bed with aching knees and a retirement he had never quite learned how to inhabit properly.
Instead — modern flat, grey morning light, the low electronic hum of unfamiliar technology.
Still here.
He lay still for a moment staring at the ceiling. The realisation settled differently this time. Not panic. Weight.
Yesterday had been survivable because it was Sunday. Domesticity required no deception beyond observation and instinct. Today was Monday. Today he had to become Colonel Lethbridge-Stewart properly — command, personnel, expectations, a life already in motion before he arrived inside it.
And somewhere beneath all of that sat a quieter, more troubling truth: he did not want to lose this yet.
That thought lingered while he shaved in front of a face thirty years too young.
The uniform helped. Military structure always had. Black UNIT fatigues instead of Brigadier greens, but close enough that muscle memory settled around him naturally once the jacket was on. The reflection staring back looked severe, capable, younger than he had any right to be. But the eyes were still his.
Kate wandered into the kitchen halfway through breakfast carrying a schoolbag that looked heavier than she did.
"You're doing the face already."
"What face?"
"The work one."
Apparently there were several faces now.
Alistair glanced toward the clock. "You'll miss the bus if you continue psychoanalysing me."
Kate narrowed her eyes slightly. "You know, you used to hate driving me to school."
That caught him. "Did I?"
"You always said traffic made you homicidal."
"…Strong wording."
"You said it after a cyclist cut you off."
"Ah. Provocation."
Kate snorted softly and reached for her toast.
The odd thing was that she seemed more relaxed this morning. Not dramatically — just lighter around him, as though yesterday had reassured her of something she hadn't known she was worried about.
That thought stayed with him all the way to the school gates.
Children flooded the pavement in noisy clusters while exhausted parents carried travel mugs like life support systems. Kate climbed out of the car, then hesitated before shutting the door.
"You'll be late."
"I'm aware."
She lingered another second anyway. Then: "…Have a good day at work."
Simple words. Yet something about the carefulness behind them tightened unexpectedly in his chest.
"You as well," he answered quietly.
Kate gave him a quick suspicious look, as though kindness from him still felt unusual enough to examine, then headed toward the school entrance. Alistair watched until she disappeared inside. Only then did he drive toward UNIT.
The Tower rose above London like a statement rather than a headquarters — glass, steel, surveillance arrays hidden inside architectural minimalism. Modern governments did so love pretending frightening things were elegant.
Security let him through instantly. Faces turned as he crossed the operations floor. Respect. Nervousness. Expectation. The Colonel belonged here. That was becoming increasingly obvious, which made the ethical discomfort worse, not better.
He was still orienting himself to the flow of the place when a familiar voice behind him said dryly: "You're either early or the building's on fire."
Alistair stopped dead. Not because of the words. Because of the voice.
He turned slowly.
Liz Shaw stood beside a bank of transparent monitors holding a tablet under one arm and wearing the expression of a woman already unimpressed by at least three people this morning. A little older than him here perhaps — early forties, sharp-eyed, controlled, brilliant.
Alive.
For one dangerous second the sheer relief of seeing her nearly broke through his composure entirely. Because in his universe — God. It had been years.
"Liz," he said before he could stop himself.
Something in his tone made her pause immediately. Not visibly to anyone else perhaps. But he saw it — saw the scientist in her register dissonance.
"You look as though you've seen a ghost," she observed carefully.
If only she knew.
Alistair mastered himself with effort. "Merely surprised."
"Hm."
Liz continued watching him in that infuriatingly perceptive way she always had. Then, after a moment: "You're in early."
Careful wording. Fishing slightly. Apparently this version of him had routines she knew well enough to notice deviations from.
"I wanted time to review current operations before the day began." True enough.
Liz tilted her head slightly. "You're usually on your second tea by now."
"I expect I shall recover the habit shortly."
That earned the faintest twitch at the corner of her mouth. Then her gaze sharpened again. "You all right?"
Simple question. Not casual. Liz had always been good at noticing fractures under surfaces.
Alistair chose his answer carefully. "I may be somewhat disoriented this morning."
"That's unlike you."
Yes. It was.
Before he could answer, an alarm flashed amber across the nearest monitor. Liz glanced toward it automatically and sighed. "Unfortunately," she said dryly, "the universe has chosen eight-thirty on a Monday for nonsense."
And despite everything — despite impossible universes and stolen lives and the terrifying uncertainty beneath his feet — Alistair felt something dangerously close to happiness at hearing Liz Shaw say that again.
The alert arrived three minutes into the morning briefing. Amber at first. Then red.
A section of East London flickered onto the main display wall while overlapping system warnings crawled rapidly down the side of the screen — energy anomaly detected, unidentified signal source, infrastructure disruption in progress.
The room sharpened instantly. Modern UNIT moved faster than the Brigadier's UNIT ever had — analysts already pulling satellite overlays, tactical response teams mobilising before half the data finished processing.
Too fast perhaps. No pause for uncertainty.
Alistair watched the information cascade across the screens.
Localised electrical failures. Transit disruptions. Reports of "lights moving underground."
Interesting wording.
"Casualties?" he asked.
"None confirmed yet," one analyst answered immediately. "But the signal pattern is spreading through utility infrastructure."
"Pattern?"
A second screen appeared. The energy spikes were not random. They moved — not geographically, sequentially. Like transmission pulses.
Alistair's eyes narrowed. "Has anyone attempted linguistic analysis?"
The room hesitated slightly. One scientist blinked. "Sir?"
"There's repetition in the intervals."
Liz looked up sharply from her tablet, then immediately started running comparisons herself without argument.
Good. Very good.
"Deploy containment teams," Alistair ordered calmly. "Non-aggressive posture unless directly threatened. Evacuate civilians quietly. I want observation before engagement."
A few surprised glances. Apparently this Colonel normally favoured stronger containment protocols.
"Yes, sir."
The operations floor exploded into motion.
Liz fell into step beside him as they headed toward the lift. "You think it's communication."
"Possibly."
"You reached that conclusion quickly."
Military instinct almost answered automatically — because I've seen this sort of thing before. Instead: "The movement pattern suggests intentionality."
"Hm."
She was studying him again. Always studying.
The lift doors opened onto the underground transport bay. Modern UNIT vehicles looked offensively sleek compared to proper military transports — too much black plating, too much design work. Someone had let politicians near procurement.
Alistair climbed into the passenger seat anyway while Liz slid in beside him still reviewing data. "What exactly are we walking into?" she asked.
"Unknown."
"That's reassuring."
"I find false confidence rarely improves survival rates."
That earned the faintest snort from her.
Good Lord, he'd missed Liz.
The drive east cut through wet London streets under low grey skies while updates continued feeding through the vehicle systems. Electrical interference worsening. Reports of voices in static. One witness claiming the Underground was singing.
Alistair caught Liz noticing that one too. "Interesting choice of description," she murmured.
"Yes."
The signal origin centred eventually near an old utility access point beneath a partially abandoned rail junction. UNIT perimeter teams had already started establishing containment by the time they arrived — civilians pushed back, emergency vehicles rerouted, armed personnel scanning rooftops and tunnel entrances.
And directly in the middle of the secured zone, a woman in a burgundy coat was arguing furiously with two UNIT soldiers.
Alistair stopped walking. Not because he recognised her immediately. Because his body did. Somewhere underneath conscious thought, every instinct abruptly aligned toward her with terrifying certainty.
Sarah.
Not Sarah Jane. Not memory. Not history. Just Sarah.
She had a torch tucked under one arm, mud on one boot, and the expression of a woman approximately thirty seconds away from climbing through the barricade whether anyone approved or not.
"I have identification," she was saying sharply.
"You're not cleared for this area, ma'am."
"I was here before you arrived."
"That doesn't help your case."
"It should actually concern you enormously."
Liz noticed him go still. Her gaze flicked toward the woman, then back toward him.
Interesting. Very interesting.
Sarah looked up then. Saw him. And stopped mid-argument.
Not romantic recognition. Not shock exactly. Something stranger — like hearing an echo in the wrong room.
Alistair felt it too. A pulse of impossible familiarity so sharp it bordered on physical pain.
Her eyes narrowed slightly as she studied him. Assessing. Calculating. Then, completely ignoring the soldiers she'd been fighting with, she pointed toward the sealed tunnel entrance behind them and said: "If your people go down there armed and frightened, they're going to make this worse."
The certainty in her voice hit him immediately. Not arrogance. Conviction backed by observation.
Alistair stepped closer slowly. "And what precisely do you believe is happening down there?"
Most people confronted by UNIT command either became defensive or intimidated. Sarah did neither.
"It's following the electrical grid," she said immediately. "But it isn't feeding."
Liz's attention sharpened.
Sarah continued, gesturing toward the pattern map displayed on a nearby UNIT tablet. "The intervals are wrong for predatory spread. It's repeating pathways."
"Repeating them toward what?" Liz asked.
Sarah glanced at her briefly. "I don't know yet."
Honest answer. Good.
Then Sarah looked back at Alistair again, and for one strange suspended moment the noise around them seemed to thin — rain against concrete, distant traffic, the low hum of UNIT equipment — all of it fading slightly under the unbearable familiarity of her face.
Different life. Different woman. Different history.
And yet — God. Even the way she looked at him was similar. Direct. Intelligent. Entirely unimpressed by authority.
"You're the Colonel," she said finally. Not a question.
"Yes."
"Hm." That tiny sound carried an alarming amount of evaluation inside it.
Then Sarah glanced once toward the tunnel entrance and added: "You're handling this more sensibly than UNIT usually does."
And somehow that felt less like praise than a test.
Rain hissed softly against concrete around them while personnel continued moving through the perimeter. Alistair studied her for another moment. The familiarity still unsettled him — not because she looked exactly like the Sarah he remembered. She didn't. Different haircut, different clothes, older around the eyes in different ways, less reckless energy perhaps, more groundedness.
But the mind behind the eyes — God. The same relentless intelligence staring directly at a problem instead of around it.
And before caution or protocol could intervene, he heard himself ask: "What would you recommend?"
One of the nearby UNIT officers looked startled enough to almost visibly flinch. Even Liz's head turned slightly toward him. Because apparently Colonel Lethbridge-Stewart did not usually solicit advice from civilians standing outside containment lines.
Sarah blinked once too. Not expecting that. Then her expression shifted almost immediately from surprise to concentration.
Good Lord. The Brigadier recognised that look instantly.
Sarah stepped toward the perimeter map on the portable UNIT monitor. "The pulses repeat every seventy-three seconds. Not uniformly — rhythmically."
Liz folded her arms. "You think it's language."
"I think it's closer to music."
Interesting. Very interesting.
Sarah pointed toward the electrical disruption pattern. "It's not damaging infrastructure as it moves. It's using it. More like resonance than transmission."
"One witness described singing," Alistair said.
Sarah nodded immediately. "Exactly."
Liz still looked cautious. "That doesn't mean intelligence."
"No," Sarah agreed. "But it suggests intent."
Again: honest. No overreach. No dramatic certainty.
The Brigadier found himself trusting that almost automatically.
Sarah crouched near the edge of the access tunnel now, listening more than looking. That, too, was painfully familiar. Most scientists observed actively. Sarah received information — the world seemed to arrive in her sideways somehow.
Then she looked up sharply. "Has anyone tried broadcasting back?"
The UNIT lieutenant nearby frowned. "Broadcasting what, exactly?"
"I don't know yet." Sarah stood again. "But if this is communication and you send armed teams into confined tunnels before attempting contact, you're establishing threat-response conditions immediately."
"That assumes it can interpret intent," Liz pointed out.
Sarah looked at her directly. "Everything interprets intent eventually."
That landed harder than it should have. Because suddenly Alistair remembered another Sarah standing in another crisis years ago arguing almost exactly the same thing about frightened creatures and frightened soldiers.
The overlap made his chest tighten unexpectedly. Liz noticed. Of course she did — her eyes flicked briefly between them before narrowing slightly in thought.
Meanwhile Sarah was still focused on the tunnel. "You said no casualties yet?"
"No confirmed injuries," Alistair answered.
"Then it's already choosing restraint."
One of the tactical officers spoke up immediately. "Or preparing escalation."
Sarah nodded once. "Possible." Again honest. No ego attached to the theory.
Then she added quietly: "But frightened things don't usually sing first."
There it was again — that impossible instinctive certainty he remembered from another universe. Not scientific arrogance. Pattern empathy. Sarah always looked for motive before weaponry.
And despite himself, despite modern UNIT procedure and the watching officers and Liz's increasingly analytical stare, Alistair trusted her. Not blindly. Never blindly. But enough.
"What do you need?" he asked.
Now Liz looked genuinely surprised — not offended, just caught off guard by how quickly he'd reached that point. Sarah looked equally startled for a fraction of a second. Then, slowly: "A quieter perimeter."
Alistair turned immediately. "Pull armed response back twenty meters. Keep evacuation lines intact but reduce visible threat posture."
The lieutenant hesitated. "Sir—"
"That is an order."
Around them UNIT personnel began repositioning while Sarah watched Alistair with an expression growing steadily more complicated. Not attraction. Not trust. Recognition of behaviour — like she had expected a fight and found cooperation instead.
"You do this often?" she asked quietly.
"Do what?"
"Listen."
The question hit him strangely hard. Because the answer in this universe might genuinely have been: not enough.
Alistair met her eyes evenly. "When someone appears to know what they're talking about, yes."
Sarah's mouth twitched faintly. Then she glanced back toward the tunnel entrance. "If I'm right, it may respond better to patterned signals than language."
"Music," Liz said thoughtfully.
Sarah nodded. "Possibly. Harmonics. Structured repetition. Something mathematical enough to establish intent."
One of the younger UNIT analysts looked faintly sceptical. "You think we should talk to it with music?"
Sarah folded her arms. "Mathematics is one of the few genuinely universal communication systems."
And before anyone else could answer, Alistair heard himself say calmly: "Music is mathematics."
Sarah looked at him immediately. Not because of the statement itself. Because of the certainty behind it — the old certainty, the kind that came from understanding the structure underneath things.
Alistair stepped closer to the display screen, studying the pulse intervals. "Ratios. Pattern recurrence. Predictive progression." His eyes narrowed slightly. "Possibly even emotional signalling through harmonic tension."
The young analyst blinked. Liz, however, looked abruptly interested. Very interested. "You have thoughts on harmonic communication theory?" she asked carefully.
Too carefully.
The Brigadier felt the trap a second too late. This universe's Colonel might not possess a physics and mathematics background remotely identical to his own. He chose his next words with caution. "I spent enough years around scientists to absorb useful habits."
Not technically untrue.
Sarah was still watching him though. Intently now. The familiarity between them sharpened unpleasantly under that gaze, because she recognised this too — not the facts perhaps, but the rhythm. The way he approached the problem. Not like a soldier humouring scientists. Like a man who genuinely understood the conceptual framework underneath the discussion.
And Sarah — being Sarah — noticed inconsistencies the way other people noticed weather.
"That's not a military answer," she said quietly.
God. The same tone. The same directness.
Alistair kept his attention on the screen deliberately. "No?"
"No." Sarah tilted her head slightly. "That's someone who actually likes mathematics."
For one dangerous second he almost smiled. Because another Sarah once accused him of exactly the same thing after catching him correcting calculations over a UNIT technician's shoulder in the seventies.
The memory hit so sharply he had to consciously remain present. Liz noticed that too. Of course she did — her gaze flicked between them both with growing scientific suspicion.
Meanwhile the signal pulsed again across the display. Seventy-three seconds. Repeating. Waiting.
And quietly, almost to himself, Alistair murmured: "It's expecting an answer."
The pulse rippled across the monitor again. Seventy-three seconds. Repeating. Waiting.
Around them the atmosphere shifted subtly as UNIT personnel adjusted to the new posture — less aggressive now, more observation than containment.
Alistair kept his attention fixed firmly on the display while part of his mind rapidly corrected a dangerous mistake. Careful. Liz had noticed far too much already. The Brigadier knew that look — the narrowing focus behind her eyes when pieces stopped fitting together cleanly. He had seen it directed at alien technology, impossible physics, and occasionally the Doctor himself. Now it was directed at him.
He mentally added another task to the rapidly growing list: determine this universe's academic history before speaking like a physicist again. Because apparently instinct was proving difficult to restrain around Sarah. Or perhaps around problems that felt familiar.
Sarah was already moving, crouching near the tunnel entrance with a portable scanner one of the technicians had reluctantly handed over after Alistair's direct order. Rain dampened loose strands of hair against her cheek as she adjusted the device settings manually. Not waiting for permission. Not waiting for institutional consensus. Just working.
Alistair watched her for a moment before he could stop himself. God, but she moved similarly. Not identically — not enough to mistake one woman for another. But the focus. The way Sarah disappeared into concentration until the rest of the world became secondary.
Painfully familiar.
Liz stepped beside him quietly. "You trust her quickly."
"She's making sense."
"She's making hypotheses."
"Evidence-based ones."
"Hm."
That thoughtful little sound again. The Brigadier resisted the urge to sigh. He would have to tread very carefully around Liz Shaw — more carefully than almost anyone else. Most people saw behaviour. Liz saw structure. And structures revealed truth eventually.
Down near the tunnel entrance Sarah looked up suddenly. "I need a speaker."
A technician frowned. "For what?"
"I'm not entirely certain yet."
"That's reassuring."
Sarah ignored him completely and looked toward Alistair instead. Not deferentially. Expectantly — like she had already unconsciously decided he was the person who made useful decisions here.
The realisation landed oddly hard. "What sort of signal?" he asked.
"I want to test response patterns first." Sarah stood, wiping rainwater absently off the scanner casing. "Simple harmonic intervals. Repetition without escalation."
Liz folded her arms. "You think it's genuinely communicative."
"I think it's behaving socially."
That sharpened Alistair's attention immediately. "How so?"
Sarah gestured toward the monitor displaying the movement pathways. "It avoids occupied sections of infrastructure. It pauses when approached aggressively. It repeats when ignored." Her eyes narrowed slightly in thought. "That's not random spread behaviour."
No. It wasn't.
The Brigadier felt the old familiar sensation settling quietly into place beneath his ribs — the moment when an alien incident stopped being chaos and began becoming understandable. He had always loved that part secretly. Not the danger. The shape underneath it.
Sarah accepted the speaker unit from a UNIT technician and crouched again near the tunnel entrance while personnel around them watched with varying degrees of scepticism and concern.
Alistair realised suddenly that everyone else was waiting for him. For the commander's line — approval, interruption, control.
Instead he found himself moving closer to Sarah. Not too close. Just enough to hear her over the rain. "What are you planning to play?"
Sarah glanced up at him briefly. And for the first time since meeting her, her expression softened into something almost conspiratorial. "Nothing complicated." Then, after a beat: "Mathematics first. Music second."
The Brigadier felt an immediate unreasonable surge of confidence in her. Not because she was certainly right. Because somewhere deep in his bones he remembered what it felt like when Sarah looked at the impossible and tried communication before conquest.
And far more dangerously — he remembered how often it worked.
The tunnel hummed softly beneath the city. Not mechanical. Not entirely electrical either. Something resonant — like standing too close to enormous machinery and feeling vibration through bone before hearing it properly.
Sarah crouched near the edge of the access point adjusting frequencies through the portable speaker while rainwater slid steadily through old concrete channels nearby. Around them UNIT held position, watching, waiting, trying very hard not to look frightened.
Alistair recognised the mood immediately. Soldiers were often most uneasy when they had not yet been permitted to define something as hostile. Sarah, meanwhile, seemed perfectly comfortable talking to the unknown. That alone would have unsettled him once. Now it simply felt familiar enough to ache.
"What are you transmitting?" Liz asked.
Sarah adjusted one of the harmonic patterns before answering. "Intervals first." Her attention remained on the equipment. "Simple repeating structures. Prime relationships. Non-random sequencing."
The young analyst frowned. "Like maths."
Sarah glanced up briefly. "Yes. Most intelligent systems recognise pattern before language."
Alistair felt himself nod slightly before he could stop it. Again that awareness flickered through him — careful, too many moments like that around Liz and she would start assembling conclusions. But the thought faded as the speaker emitted a soft sequence of tones into the tunnel below.
Three notes. Pause. Three notes again.
Nothing happened immediately. Then the lights beneath the street flickered. Not failure. Response.
Every monitor around the perimeter shifted at once as the energy pulse altered direction sharply underground — toward them. Several UNIT soldiers instinctively tightened their grips on their weapons.
Sarah noticed without turning around. "Easy," she said quietly. Not commanding. Calming.
The strange hum deepened beneath the pavement. The speaker crackled suddenly. Then answered.
Not words. Tones. Layered. Complex. Almost choral.
The entire perimeter went still. The sound wasn't frightening exactly — too structured for that. It carried intention.
Alistair watched Sarah's face carefully as she listened. Not fear there either. Concentration. She altered the sequence slightly. The tones from below changed almost immediately in return.
Liz took a step closer. "It's adapting."
"Yes," Sarah whispered. Fascinated now.
The underground lights pulsed in synchronised waves beneath the street grid displayed across UNIT monitors. Communication. Actual communication. The realisation rippled visibly through the personnel around them, excitement warring with unease.
Sarah sent another sequence. This time the answer came faster.
More complex.
The humming beneath their feet shifted again and suddenly Alistair understood what had been bothering him about the movement pattern. Not hunting. Not spreading. Searching.
"They're trying to localise the signal source," he said quietly.
Sarah looked up sharply. "Yes."
Again that immediate agreement between them. Too immediate.
Liz absolutely noticed this time. Alistair saw it from the corner of his eye — the growing scrutiny settling behind her expression.
Later problem.
Right now the important thing was the thing beneath London apparently attempting first contact through municipal electrical infrastructure.
Sarah slowly stood, eyes fixed on the monitor patterns. "I don't think they intended to scare anyone."
One of the UNIT officers nearby looked dubious. "They shut down half the transit grid."
Sarah nodded once. "Because they don't understand what they're inside."
That landed heavily.
Alistair looked back toward the tunnel entrance. Alien intelligence loose inside the infrastructure of one of the largest cities on Earth. Another universe. Another century. Same impossible choices.
"What are they asking?" he said quietly.
Sarah was silent for a moment, listening again to the layered harmonic responses echoing faintly from underground. Then she answered slowly: "I think…"
The tones shifted again beneath them. Softer this time. Questioning.
Sarah's eyes widened slightly. "Oh."
"What?" Liz asked immediately.
Sarah looked back toward them both. And for the first time since this began, genuine emotion crossed her face. Not fear. Sympathy.
"They're lost."
The words settled heavily across the rain-soaked street. Around them the humming beneath London continued softly through the infrastructure grid, less frightening now that intention had emerged from the noise.
Lost. Not invading. Not feeding. Not attacking. Searching.
One of the UNIT tactical officers spoke first. "Sir, with respect, we still don't know what they're capable of."
Sensibly cautious. Alistair nodded once. "Agreed."
Sarah watched him carefully then, as though waiting to see which instinct won. Containment. Or compassion.
The Brigadier looked back toward the tunnel entrance. And unexpectedly, painfully, he understood the feeling beneath the harmonic patterns. Dislocation. Confusion. The desperation of unfamiliar systems and no way home.
"Can we help them find their way back?" he asked quietly.
Sarah blinked. Not because of the question itself. Because he had asked it first.
Rain tapped steadily against the portable equipment while the humming below shifted almost uncertainly through the electrical lines.
"I think so," Sarah answered slowly. "If we can determine how they arrived."
Liz was already moving toward one of the mobile analysis stations. "The energy profile is inconsistent with standard transit breach signatures," she said while pulling data onto the nearest display. "No wormhole residue. No measurable dimensional rupture."
"Then perhaps they didn't come physically," Alistair murmured.
That drew both women's attention immediately. He could almost hear himself sounding too knowledgeable again.
Careful.
But the thought had already formed fully. "They may have followed signal propagation rather than spatial transition."
Sarah's eyes sharpened instantly. "Like transmission drift."
"Yes."
Liz frowned thoughtfully at the display. "That would explain why they integrated into infrastructure instead of materialising conventionally."
Sarah moved closer to the monitors now, rain forgotten entirely. "If they're energy-based intelligences using harmonic mapping to navigate…" Her expression changed abruptly. "Oh, that's clever."
"What?" Alistair asked.
"They might not even understand they crossed systems."
Liz looked up sharply. "Meaning?"
Sarah gestured toward the pulse maps. "If their method of travel is resonance-based rather than physical movement, they may perceive electrical infrastructure the way we perceive roads."
That silenced everyone for a second. Because suddenly the incident transformed from invasion into accident. The aliens hadn't burrowed into London deliberately. They had taken a wrong turn.
Alistair felt something inside him settle into certainty then. Not certainty of success. Moral certainty.
"We find them a route home," he said simply.
One of the officers hesitated. "Sir, if they're capable of destabilising the national grid—"
"Then frightening them further would be exceptionally unwise."
That ended the objection.
Sarah looked at him again then. Really looked — not at the rank, not at the command posture, but at him. And the strange thing was that Alistair recognised the expression. Not from this Sarah. From another life. That quiet moment when she realised he had chosen understanding over aggression and had not needed persuading into it.
It made his chest ache unexpectedly.
Liz interrupted before the silence could deepen. "If we're attempting directed resonance mapping, we'll need broader signal triangulation." She glanced toward Alistair. "UNIT can access national grid architecture."
"Do it."
Orders snapped outward immediately across comms channels — satellite synchronisation, power infrastructure overlays, signal harmonics mapped against transit pathways. Modern UNIT moved beautifully when properly directed.
Alistair found himself slipping naturally into command as personnel reorganised around the new objective. Not containment now. Guidance.
And somewhere beneath the operational focus, another realisation moved quietly through him. He understood these creatures because he was one. Not alien. Displaced. Lost somewhere that looked enough like home to hurt.
Sarah crouched beside the speaker again and transmitted another sequence into the tunnel. Gentler this time. Questioning.
The response came almost instantly. The lights beneath the street brightened in soft waves. Not random. Hopeful.
And before he could stop himself, Alistair stepped closer beside her. "If they can perceive harmonic structure," he said quietly, "perhaps we can build them a navigational framework."
Sarah looked up at him immediately. Not surprised he understood. Almost as though she had expected him to.
The operation shifted gradually from containment to construction. UNIT personnel rerouted portions of the city grid under Liz's direction while portable harmonic emitters were brought in from research divisions three floors underground. Across the command displays, London's electrical infrastructure began transforming into layered patterns of light and frequency mapping. A pathway. Or at least the beginning of one.
Rain continued falling steadily across the barricades while Sarah worked crouched beside the primary signal array, sleeves pushed up carelessly and hair steadily escaping whatever attempt she'd made to keep it under control earlier.
Alistair found himself watching her more than the equipment. Not romantically. Not yet. Recognition again — the old dangerous familiarity of seeing someone think in motion. Sarah didn't approach science linearly. She circled it. Tested edges. Looked for emotional structure inside mathematical systems.
It reminded him far too much of another life.
"Try reducing the tertiary interval," he said quietly as he stepped nearer. Not loudly enough for the wider team.
Sarah glanced up immediately. "Why?"
"The response lag increased after the last sequence."
Understanding flashed across her face almost instantly. "Yes," she murmured. "It's oversaturating the harmonic bridge."
She adjusted the sequence manually. The lights beneath the streets stabilised at once. Several technicians nearby looked startled. Sarah looked sideways at him instead.
Interested now. Very interested.
Alistair immediately regretted speaking. Too precise. Too instinctive. And somewhere behind them Liz Shaw was still very much present — he could practically feel the danger of her attention whenever he forgot himself.
So he stepped back slightly and folded his hands behind his back with deliberate military neutrality.
Sarah hid the faintest trace of amusement badly.
She'd noticed that too.
The harmonic patterns shifted again across the monitors. This time the answering pulse flowed smoothly through the mapped infrastructure routes rather than scattering chaotically across the grid. The humming beneath the city softened. Not gone. Calmer.
"They understand directional sequencing now," Sarah said quietly.
Liz looked up from the analysis station. "You're certain?"
"No." Sarah adjusted another frequency band. "But I think they understand we're trying to help."
That word again. Help. Not contain. Not repel. Not neutralise. Help.
Alistair realised suddenly how strange this entire scene would look to modern UNIT doctrine — a civilian scientist kneeling in the rain teaching lost alien intelligences how to navigate home through London's power infrastructure while armed military teams stood by waiting for instructions. And somehow everyone had accepted it because she was making the impossible feel understandable.
The Brigadier remembered that feeling too.
Sarah paused suddenly over the control interface. "No…"
"What?" Liz asked immediately.
Sarah stared at the harmonic readings, frowning. "The framework's incomplete."
Alistair saw it a second later. The return signal weakened every time it reached the edge of the mapped corridor.
"They don't only need direction," he murmured quietly.
Sarah looked at him instantly. "They need continuity."
There it was again — that immediate meeting point between their thoughts. Dangerous. Comforting. Unnerving.
Sarah nodded slowly. "If the resonance bridge collapses before transition completes, they'll scatter back into the grid."
Liz was watching both of them openly now. Not suspicious exactly. But tracking. Connecting.
Alistair felt the weight of that attention and chose his next words carefully. "Can the framework sustain itself once initiated?"
Sarah considered the problem, eyes narrowing thoughtfully toward the pulse maps. Then suddenly: "Oh, that's clever."
"What?" Liz asked.
Sarah pointed toward the city infrastructure overlay. "We've been thinking too locally." She looked up toward the relay towers visible against the skyline beyond the rain. "The whole grid already functions like a harmonic network."
Understanding clicked immediately into place for Alistair too. She saw it. Of course she did.
"We don't build a corridor," Sarah said, standing now with growing excitement brightening her entire face. "We teach the system the pattern and let London carry them home."
Several UNIT technicians exchanged startled looks. Liz stared at the display for one long second. Then, very quietly: "That might actually work."
Sarah looked absurdly pleased by that.
And despite himself, despite every warning bell in his head about familiarity and memory and impossible emotional overlap, Alistair felt a sharp, private surge of pride watching her. Because once again Sarah was standing in the middle of fear and choosing understanding first. And somehow, impossibly, the universe still became better around her when she did.
London learned the pattern.
That was what it looked like in the end. The city itself began carrying the harmonic framework through its infrastructure — electrical systems, underground rails, communications relays all echoing the carefully structured resonance Sarah had built. Across the monitors, the scattered pulses gradually stopped behaving like frightened static. They aligned. Not perfectly. But intentionally.
The humming beneath the streets deepened once, resonant enough that several people around the perimeter instinctively looked down toward the pavement. Then the lights across the tunnel system flickered in synchronised waves, one after another, moving outward. Away.
Sarah stood very still beside the signal array, eyes fixed on the readings while the harmonic bridge propagated through the city grid. Alistair watched the pulse pattern retreat steadily across the infrastructure map. East. Then south. Then gone.
Not extinguished. Released.
The silence afterward felt enormous. No more humming. No more distortion through the electrical systems. Only rain against concrete and the distant noise of ordinary London slowly returning around them.
One of the analysts stared at his monitor. "The signal's vanished."
"No," Sarah said quietly. She was still looking at the final harmonic traces fading from the system. "They left."
God. Even now she phrased it like people rather than phenomena.
Alistair felt something inside him ease unexpectedly. Not victory. Relief.
The perimeter gradually relaxed around them as UNIT teams began standing down — weapons lowered, emergency protocols collapsed back into ordinary procedure. Crisis over. Or at least this one.
Liz was already moving toward the operations teams issuing rapid instructions for data preservation and systems review, but not before casting one long measuring look toward Alistair and Sarah both.
Too perceptive by half.
The Brigadier felt caution settle sharply back into place. He had let himself forget it briefly while the work mattered more than the deception. That could not continue.
Sarah powered down the portable array slowly, rainwater dripping from the edge of her sleeve. She looked tired now that concentration was fading. Satisfied too.
Alistair stepped toward her automatically — then checked himself halfway there. Distance. Necessary now. He stopped a more formal distance away instead, hands settling behind his back in practiced military posture.
Sarah noticed immediately. Of course she did. Her eyes flicked across him once, reading the change almost instantly. Not hurt exactly. Just awareness.
"The situation appears resolved," Alistair said evenly.
God, that sounded cold. Professional. Controlled. Safe. He hated it immediately.
Sarah tilted her head slightly, studying him. "Yes," she answered after a moment. "Looks that way."
The familiarity between them retreated behind formal edges again. Necessary. Because Liz was still watching from thirty feet away while pretending very hard not to.
Alistair forced himself to maintain the distance. "UNIT appreciates your assistance, Doctor Smith."
There. Official. Measured. Public.
Not the truth of what he actually wanted to say, which was closer to: you saved them, you were right, you made the world kinder today.
Sarah seemed to hear some trace of that anyway. Her expression softened very slightly. "You listened," she said quietly. Not praise. Observation.
Alistair kept his face carefully neutral. "Your recommendations proved effective."
Again: too formal. He could hear it himself. Sarah could too. The rain between them suddenly felt colder.
For one dangerous second he nearly abandoned the caution entirely — nearly stepped back into the easy instinctive rhythm that had formed between them during the crisis. Then he caught sight of Liz in the background speaking to two analysts while still tracking him in her peripheral vision like a scientist observing unstable particles.
No. Not yet. Too risky. Especially around Liz.
Sarah followed his gaze briefly. Understood immediately. That startled him almost as much as everything else about her — not the specifics perhaps, but the withdrawal, the caution, the sense that something complicated sat underneath his behaviour. And instead of pushing, she simply nodded once. Professional courtesy returned like a mask sliding into place.
"Well," she said lightly, "try not to militarise any more lost tourists before lunch."
The Brigadier almost smiled. Instead he inclined his head slightly. "I shall endeavour to restrain the organisation."
"That'll be a first."
And there she was again for half a second — sharp-eyed, impossible, faintly amused at authority itself.
Then Sarah picked up her equipment and stepped back through the perimeter lines into ordinary London, leaving behind only damp footprints and an operations team still trying to process the fact that they had just talked alien intelligences home through the city electrical grid.
Alistair watched her go far longer than he should have.
Then quietly, without looking toward her, Liz appeared beside him and said: "You know her remarkably well for someone you've supposedly just met."
Damn.
Alistair kept his gaze fixed on the retreating figure of Sarah disappearing through the rain beyond the UNIT perimeter. Play this carefully. Too sharp a denial and Liz would smell blood immediately. Too much truth and he risked opening doors he was nowhere near prepared to walk through.
So instead he chose the oldest military tactic available: confusion.
"I beg your pardon?"
Beside him, Liz gave him a flat look entirely unimpressed by the performance.
"You trusted her very quickly."
"She was correct."
"That isn't what I said."
No. It wasn't.
Alistair folded his hands behind his back more firmly, posture settling into measured neutrality. "The woman demonstrated expertise in xenocommunication theory, pattern analysis, and harmonic systems under operational pressure," he said evenly. "Ignoring useful intelligence because it originates outside UNIT would be idiotic."
"That," Liz replied dryly, "was an excellent strategic answer."
Dangerous woman.
Alistair allowed himself the faintest sigh. "You disagree?"
"No." Liz glanced toward the now-stable monitors where London's infrastructure was gradually returning to normal. "Actually I think she was brilliant."
There was no jealousy in her voice. Which somehow made it more dangerous. Because Liz was not reacting emotionally — she was observing, tracking. And scientists were often far more frightening than jealous people.
"She also deferred to you unusually quickly," Liz continued.
That caught him slightly off guard. "Did she?"
"Yes." Liz adjusted the tablet under her arm absently. "Most civilians either become intimidated by UNIT command structures or aggressively oppositional. Doctor Smith…" Her mouth twitched faintly. "Did neither."
That was painfully true.
"She behaved as though she expected you to listen."
Alistair forced himself not to react. Barely.
"Perhaps she found me reasonable."
Liz turned fully toward him then, rain darkening the shoulders of her coat. "Are you?"
God, he'd missed this.
The relentless precision of her mind. The way she peeled at assumptions until structure showed through underneath.
Unfortunately, at present, the structure underneath him was an interdimensional identity crisis. Best not to share that.
"I attempt to be," he answered mildly.
"Hm." That thoughtful sound again. Then, unexpectedly: "You seem happier today."
Alistair blinked once. That was not where he expected the conversation to go.
"Happier."
"Yes." Liz studied him with unsettling calm. "Yesterday you nearly bit a procurement officer's head off over drone budgets."
"That sounds entirely reasonable."
"It probably was." A pause. "But today you stood in the rain helping a civilian scientist teach lost aliens how to navigate home."
The words settled strangely between them. Not accusation. Not criticism. Observation. And beneath it, perhaps, relief.
Alistair looked away toward the quiet tunnel entrance. "Circumstances differed."
"No." Liz's voice softened fractionally. "You did."
That landed far too close to truth.
He could feel the edges of danger around the conversation now. Liz wasn't suspicious because of romance or favouritism. She was suspicious because Colonel Lethbridge-Stewart appeared subtly but fundamentally altered overnight — different priorities, different instincts, different emotional responses. And Liz Shaw noticed systems changing. Even human ones.
So Alistair did the only sensible thing available. He retreated further behind professionalism. "I expect the incident reports will require review."
A blatant deflection. Liz noticed that too, naturally. But after a long moment she simply nodded once.
"Tea first."
That startled an almost genuine smile out of him before he could stop it. Not because of the tea. Because it was such an absurdly familiar Liz answer that for one impossible moment he felt like himself again instead of a ghost wearing another man's life.
Liz saw the reaction instantly. And for the first time since this conversation began, something flickered across her face that looked less like scientific curiosity and more like concern.
Tea happened in Liz's lab. Of course it did. Some things, apparently, transcended universes.
The lab itself was far more modern than anything UNIT had possessed in his own time — transparent displays layered across workstations, active modelling systems suspended holographically over central tables, equipment that would once have looked like science fiction humming quietly in ordered rows.
And in the middle of all of it: a battered electric kettle, proper mugs, tea strong enough to repair structural damage.
Liz handed him a cup without asking how he took it. That hurt unexpectedly. Not because it was intimate. Because it was familiar.
Alistair accepted the tea carefully and reminded himself — not for the first time — that familiarity was dangerous now. Especially with Liz. Sarah unsettled him emotionally. Liz endangered him intellectually. There was a difference. Sarah operated instinctively, empathetically — she noticed truths about people because she listened to them. Liz dissected patterns. And right now he was the pattern.
"You're very quiet today," Liz observed casually while pulling up harmonic residue scans across one of the displays.
There it was again. Observation disguised as conversation.
Alistair kept his attention on the tea. "I imagine the morning required concentration."
"Mm." Not disagreement. Data collection.
God help him, he knew that sound too well.
Liz moved around the workstation with efficient precision while the silence stretched between them. Not uncomfortable. Potentially dangerous. Because the longer it lasted, the more likely she became to fill it with questions. And Alistair could not afford questions. Not yet. Possibly not ever.
He found himself studying her covertly over the rim of his mug. Older than the Liz he remembered from UNIT days perhaps, but still unmistakably herself — sharp-minded, controlled, slightly impatient with stupidity at all times.
Trusted once. That was the painful part.
The Brigadier had trusted Liz Shaw with his life. Repeatedly. But this was not his Liz. This woman belonged to this universe, this UNIT, this version of Alistair. And if she learned the truth too early — he genuinely did not know what would happen. Containment perhaps. Investigation certainly. Questions he could not answer ethically. What happened to the original consciousness? Was it displaced? Destroyed? Suppressed?
The thought still made him feel faintly ill.
So he chose caution instead. Distance.
Liz glanced toward him suddenly. "You're doing it again."
His grip tightened imperceptibly against the mug. "Doing what?"
"Leaving the room while still physically present."
Too perceptive. Always too perceptive.
"I'm merely thinking."
"No." Liz leaned lightly against the workstation, studying him openly now. "You're editing yourself before you speak."
Damn.
Alistair forced himself not to react. "You appear unusually interested in my conversational habits."
"Because they changed overnight."
There it was. Directly now. No more circling.
The lab hummed softly around them while rain continued streaking down the high windows beyond the city skyline. Alistair set the tea down carefully before he betrayed tension physically.
"What precisely are you implying, Doctor Shaw?"
Liz's eyes narrowed very slightly at the formality. Good. Let her notice it. Distance was safer.
"I'm implying," she said evenly, "that you've spent years treating every conversation like a battlefield briefing and today you suddenly sound…" She searched for the word. "Older."
His pulse gave one hard, unpleasant thud.
He rose smoothly before she could continue, military posture settling around him like armour. "I expect the incident reports require final authorisation."
A retreat. Blatantly so. Liz knew it immediately. But this time when she looked at him, the concern beneath her scrutiny had become unmistakable. Not romantic. Not suspicious exactly. Worried.
That somehow made everything worse. Because it reminded him too painfully of the years when Liz Shaw had been one of the few people in the world he could stop performing competence around.
He could not afford that mistake here. Not again.
So Alistair straightened his jacket with precise economy and stepped back toward the door. "Thank you for the tea." Formal. Controlled. Cold enough to create safety.
Liz watched him for a long moment without answering. Then quietly: "You know, whatever's happened to you—"
Alistair froze internally. But her voice remained careful.
"—you don't have to handle it alone."
God.
For one catastrophic second he nearly told her. The exhaustion. The impossible displacement. The terrible relief of seeing familiar faces in unfamiliar lives. Then survival instinct reasserted itself sharply. Because trust here would not be simple. Not safe. Not clean. And the Brigadier had survived long enough to know that loneliness was often preferable to becoming someone else's incident report.
So instead he inclined his head once. "You're very kind, Liz."
Not an answer. Never an answer. And then he left before she could ask another question.
The rest of the workday passed in careful restraint. Alistair stayed inside the structure of command because structure was safer than thought — reports, debriefs, infrastructure assessments, political calls about public messaging that made him miss the comparative simplicity of UNIT in the seventies.
All the while he remained acutely aware of two things.
First: Liz was watching him. Not constantly. Not obviously. But enough — a scientist tracking anomalous data points.
Second: he did not want to lose this.
That realisation had settled fully into place sometime around midafternoon while reviewing incident summaries from the tunnel operation. The fear surprised him by its intensity. Not fear of death. Not fear of exposure. Fear of absence. Because for the first time in years — perhaps decades — he was going home to someone waiting there.
Kate. Eleven years old. Alive. Talking about school and stealing biscuits and correcting his driving.
A second chance so impossible it felt dangerous even to want it. And Liz asking the wrong questions could shatter all of it. Or worse: the truth itself could.
By the time he finally left UNIT Tower, exhaustion sat heavy behind his eyes. Not physical exhaustion. The strain of editing himself constantly. He had forgotten how tiring deception could become when performed around intelligent people.
The drive to Kate's school settled him slightly. Children leaving through the gates in noisy swarms. Parents waiting in clustered lines. Ordinary life continuing stubbornly beneath impossible circumstances.
Kate spotted him immediately and brightened faintly before trying to hide it behind practised eleven-year-old composure. "You're late."
"Three minutes."
"That's basically abandonment."
"Remarkable survival rate under the circumstances."
Kate dumped her bag into the backseat and climbed in. "You look tired."
"Work was eventful."
"Alien eventful or paperwork eventful?"
"…Both."
"Oof."
Alistair found himself almost smiling again.