Chapter Text
It started, as most UNIT disasters did, with the best of intentions. The Black Archive's annual holiday party was in full swing, the normally sterile vaulted ceilings transformed by twinkling fairy lights that reflected off glass display cases containing artifacts that really shouldn't have been near eggnog. The air smelled of pine needles, spiced cider, and the faint ozone tang that always lingered around the dimensional rift in Sector 7.
Kate Stewart stood near the refreshment table, nursing a cup of tea that was definitely spiked (she'd already caught three junior agents giggling suspiciously near the "non-alcoholic" punch). Her sharp eyes scanned the room, noting Petrovich from Xenobiology attempting to teach the new recruits an alien drinking game, while Dr. Chang was engaged in what appeared to be a heated debate about tinsel tensile strength with two engineers.
She didn't notice the mistletoe.
Osgood, however, had been acutely aware of the offending plant since arriving. Being Osgood, she'd immediately calculated:
- Its exact position (2.3 meters above the punch bowl, 37 degrees northeast of the main entrance)
- The tensile strength of the fishing line suspending it (approximately 4.5 kg)
- The statistical probability of someone being caught beneath it during peak party hours (87.6%)
What she hadn't accounted for was the speed at which UNIT's collective scientific mind would work when presented with such an opportunity. Within minutes of its appearance, an entire covert operation had sprung into action. Josh had "accidentally" redirected foot traffic toward the refreshments. Dr. Petrovich had engaged Kate in an unnecessarily lengthy discussion about Krampus particle physics near the punch bowl. Three junior researchers were maintaining a discreet but obvious betting pool by the canapés.
Osgood adjusted her glasses for the fourth time in as many minutes, her clipboard clutched like a shield. She was halfway through calculating escape trajectories when she looked up to find Kate suddenly beside her, holding two cups of punch. "You looked like you could use this," Kate said, offering one glass. Then she frowned. "Why is it so quiet all of a—"
The room had gone dead silent. Even the background holiday music (a carefully curated playlist of Earth Christmas songs and Rigelian solstice chants) had mysteriously cut out. Osgood's eyes darted upward meaningfully.
Kate followed her gaze. "Oh for—" She pinched the bridge of her nose. "Who put that there?"
A chorus of innocent "Not me"s erupted from around the room, suspiciously well-coordinated for spontaneous denials. Josh suddenly found the ceiling fascinating. Petrovich developed an intense interest in his shoes.
Osgood's fingers twitched toward her inhaler before she stopped herself. "You're, um. Standing directly beneath it," she managed, her voice only cracking slightly. "The mistletoe, I mean. Which has an interesting history actually—the tradition dates back to pre-Christian European—"
"So are you," Kate interrupted, her tone drier than the Sahara. Her military posture didn't change, but Osgood noticed the slightest tightening around her eyes—the same expression she wore when dealing with particularly stubborn alien diplomats.
From somewhere near the quantum destabilizer display, someone stage-whispered, "Just kiss already!"
Osgood was fairly certain her face now matched the colour of the emergency alarms. The temperature in the room seemed to have increased by at least ten degrees. She could feel seventeen pairs of eyes burning into them, plus whatever unseen observers were undoubtedly monitoring from the security booth.
Kate's sigh could have powered a small turbine. "Right." She turned sharply to the assembled scientists. "Who's responsible for this?"
The resulting silence was so complete Osgood could hear the faint hum of the Archive's force fields. Then, as if on cue, the entire staff suddenly found urgent business elsewhere—examining decorations, studying data pads, or in one memorable case, pretending to be deeply engrossed in a conversation with a potted plant.
Osgood's scientific mind raced through options. She could:
1) Feign a medical emergency (low probability of success)
2) Initiate a fire drill (ethically questionable)
3) Remove the problem at its source
Option three won out. Before Kate could react, Osgood reached up on tiptoes (the mistletoe was hung just slightly too high, likely by design) and plucked the sprig from its fishing line. She tucked it decisively into her lab coat pocket, where it couldn't cause any more trouble.
"There," she said, adjusting her glasses with more confidence than she felt. "Crisis averted."
The collective groan of disappointment from their audience was almost comical in its synchronization. Three junior scientists near the dessert table actually slumped in defeat. Someone muttered darkly about "wasted opportunities" and "year-long bets."
Kate's lips quirked in that barely-there smirk Osgood had catalogued in her private mental files (Expression #27: Amused But Trying Not To Show It). She leaned in just close enough that her breath ghosted past Osgood's ear, sending an entirely unscientific shiver down her spine.
"You do realize," Kate murmured, voice low enough that only Osgood could hear, "that this is only going to make it worse, don't you? By tomorrow there'll be conspiracy theories in the break room." Osgood swallowed hard; her throat suddenly dry.
"Probably," she admitted. "But at least now we can make a strategic retreat."
Kate nodded once, that familiar glint of tactical understanding in her eyes. Together they turned and strode toward the exit, shoulders brushing as they navigated through the crowd of disappointed scientists. Behind them, Osgood distinctly heard:
- An exaggerated sigh
- Someone whispering "they're so perfect together"
- The unmistakable sound of money changing hands
As the Black Archive's doors hissed shut behind them, cutting off the renewed buzz of conversation, Osgood let out a breath she hadn't realized she'd been holding. The cooler air of the corridor was a relief against her flushed face.
Kate shook her head, glancing at Osgood with that particular mix of exasperation and fondness reserved for situations only UNIT could create. "Well. That's another year's worth of rumours secured." Osgood patted her pocket where the mistletoe lay safely contained.
"At least until they find the backup sprigs. I counted at least three more being passed around when we left." Kate groaned.
"Why do I employ so many brilliant idiots?"
"Because they're the only ones who can keep up with you," Osgood said before she could stop herself. Then froze. "I mean—that is—professionally speaking—"
The look Kate gave her was unreadable. Then, with perfect timing, the overhead speakers crackled to life with an all-too-familiar voice: "Attention all personnel," Josh announced, barely containing his glee, "we've got a Code Silver in the main lab. Repeat, Code Silver. That's mistletoe-related incidents for you new recruits."
Kate closed her eyes briefly, as if praying for patience. "I need a drink."
"Technically, you already had one," Osgood pointed out. Then, at Kate's look: "But I know where you keep the good Scotch."
As they walked down the corridor together—UNIT's most speculated-about almost-couple—Osgood couldn't help but notice they were walking just a fraction closer than protocol dictated. And if Kate's hand brushed against hers when they turned the corner, well—that was surely just a coincidence.
---
The Next Morning
The UNIT canteen at 07:45 was a study in controlled chaos—scientists nursing mugs of strong tea, security personnel inhaling breakfast sandwiches between shifts, the occasional alien consultant eyeing the toast racks with suspicion. Normally, Osgood found the predictable rhythm comforting. Today, the moment she stepped through the double doors, the ambient noise dipped by approximately 37% before surging back with renewed, poorly concealed interest.
She should have known better than to hope the mistletoe incident would fade overnight. UNIT’s rumour mill operated with the efficiency of a quantum supercomputer—if said supercomputer were programmed by over-caffeinated romantics with too much clearance and not enough common sense.
The new mistletoe hung directly above the coffee machine, suspended by what appeared to be military-grade adhesive (the kind usually reserved for securing alien containment cells). The accompanying sign—"For Scientific Research Purposes Only"—was written in Josh’s distinctive scrawl, complete with a poorly drawn heart substituting the "o" in "Purpose."
Kate stood before it like a general surveying a battlefield, her usual immaculate trouser suit somehow making the industrial canteen look like a war room. The morning light through the reinforced windows caught the silver in her hair as she glared at the decoration, her arms crossed in a way that made junior agents two tables over instinctively straighten their postures.
"Tell me," she said without turning, her voice carrying that particular blend of exasperation and authority that made even senior staff reconsider their life choices, "is this what passes for subtlety in the sciences division now?"
Osgood adjusted her glasses, the frames clicking softly as she took in the scene. The mistletoe’s positioning wasn’t just obvious—it was tactically brilliant. The coffee machine was UNIT’s most frequented station, guaranteeing maximum exposure. The height required both of them to reach up, ensuring proximity. And the choice of adhesive suggested someone had raided the xenobiology lab’s emergency supplies.
"I think," Osgood said carefully, "they’ve abandoned subtlety entirely. This has Petrovich’s fingerprints all over it—literally." She pointed to the faint blue residue on the tape. "That’s Andromedan polymer glue. He’s been experimenting with it for—"
"Yes, thank you," Kate cut in, though her lips twitched. Then, in perfect unison, they both reached for the mistletoe.
The moment stretched—Kate’s fingers, usually so precise when disarming alien tech or signing classified documents, brushed against Osgood’s as they grasped the sprig. Osgood’s breath caught. The contact lasted no more than 0.8 seconds, but her nervous system registered it with the intensity of a solar flare. Her fingers tingled where Kate’s had touched them, the sensation racing up her arm like an electric current. She fumbled the mistletoe, barely catching it before it hit the floor.
Kate arched one perfectly sculpted eyebrow. "Nervous?" Osgood’s pulse thundered in her ears.
"No," she lied, pushing her glasses up her nose with her free hand. "Just—calculating the structural integrity of the tape. The tensile strength-to-adhesion ratio is—"
"Mm." Kate’s smirk said she wasn’t fooled. She plucked the mistletoe from Osgood’s grip, her fingertips lingering just a heartbeat too long. Turning it over in her hands, she examined the leaves with the same focus she’d give an alien artifact. "We’re never living this down, are we?" Osgood busied herself adjusting her scarf—the blue one Kate had complimented last winter. The wool suddenly felt too warm against her skin.
"Not unless we fake our own deaths," she quipped. Then, before her brain could engage its filter: "Or—alternatively—kiss in front of everyone and get it over with."
The words hung between them, vibrating in the air like a misfired sonic screwdriver.
Kate went utterly still. The canteen’s background noise faded to a distant hum as Osgood’s brain scrambled to backtrack—it was a joke, obviously a joke, why would she ever think—
Then, slowly, deliberately, Kate’s lips curved into that dangerous half-smile Osgood had seen her use on hostile alien ambassadors right before she outmanoeuvred them. "Is that an option you’d consider, Dr. Osgood?" Osgood’s mental processes short-circuited. Somewhere in the back of her mind, a calm, rational voice noted that her pulse had spiked to 128 bpm.
"I—that is—" She swallowed. "It was a theoretical suggestion. Purely hypothetical. Like... like testing event horizons. Or dark matter interactions." Kate leaned in, just enough that Osgood caught the faint scent of her bergamot shampoo mixed with gunpowder residue (likely from yesterday’s Level 3 containment breach).
"Because if we did," she murmured, low enough that only Osgood could hear, "it would certainly shut them up."
Osgood’s breath hitched. Kate’s eyes—usually so focused and analytical—held an unfamiliar glint, something warm and teasing and—
The canteen doors burst open with enough force to rattle the cutlery. A gaggle of junior researchers tumbled in, their hastily assembled "casual conversation" about plasma coils fooling absolutely no one. Behind them, Osgood spotted Josh hastily pocketing his phone—undoubtedly capturing the moment for UNIT’s underground betting pool.
Kate straightened with military precision, the moment shattered. With perfect aim, she tossed the mistletoe into the nearest biohazard bin. "Right," she announced, her commanding-officer voice snapping the room to attention. "Back to work, everyone. The Earth won’t save itself."
As the crowd reluctantly dispersed—though not without significant meaningful glances—Osgood let out a slow exhale. Her fingers tingled where Kate’s had touched them. The canteen’s fluorescent lights buzzed overhead, mingling with the whispers already spreading through UNIT’s comms network.
Somewhere, Petrovich was probably taking new bets.
This, Osgood decided as she mechanically poured coffee she no longer wanted, was going to be a very long December.
--
By Thursday, the situation had escalated to DEFCON 2 levels of absurdity. Osgood discovered this when she entered Lab 3 to retrieve the Thalixian energy readings and found Dr. Petrovich holding court before a whiteboard that would have made MI5's conspiracy theory wall look amateurish.
The board displayed:
- A colour-coded timeline stretching back six months (blue for "professional interactions," pink for "alleged romantic tension")
- Photographic evidence including three blurry cafeteria shots and one startlingly clear image of them sharing an umbrella
- A detailed analysis of their estimated "glances per hour" ratio
- A flowchart titled "Pathways to True Love (UNIT Edition)"
Petrovich, mid-sentence to a rapt audience of junior researchers, froze with his marker hovering over a newly added "Hand Brushing Incident (Coffee Machine, Dec 12)." The chemical smell of dry-erase markers mixed with the sharp tang of panic sweat in the suddenly silent lab.
"I can explain—" Petrovich began, his Russian accent thickening with guilt as he made a desperate lunge to erase the evidence. Osgood adjusted her glasses with deliberate calm, the lenses flashing under the lab's harsh LED lights.
"Don't bother," she sighed, stepping forward to examine the board more closely. Her trained eye immediately noted the disturbing level of detail—someone had even cross-referenced their duty rosters for "coincidental overlaps." She tapped the odds written in the corner. "Just tell me what probability you're giving for 'never.'"
The resulting silence was so absolute Osgood could hear the hum of the electron microscope in the adjacent lab. Somewhere in the back, a beaker shattered on the floor, its crystalline pieces skittering across the epoxy-coated concrete. The new intern from Cambridge looked ready to faint.
Petrovich swallowed audibly. "Current betting pool has 'never' at 15-to-1," he admitted. Then, with the reckless bravery of a man who'd faced down Sontarans, added, "Though after the coffee machine incident yesterday, odds dropped to—"
"I don't want to know," Osgood interrupted, her voice clipped. She made a show of studying the board for three more excruciating seconds before turning on her heel. As the lab door hissed shut behind her, the explosion of whispers was almost loud enough to trigger the sound-dampening protocols.
++
Meanwhile, twelve floors up in the executive wing, Kate Stewart was experiencing her own special hell. Her normally unflappable assistant, Rebecca, had developed a new habit of sighing wistfully every time Osgood's name appeared in reports. The latest instance came as Kate dictated a memo about the upcoming Venusian delegation.
"—and ensure Dr. Osgood's team has prepared the—"
Rebecca sighed. Not a normal sigh. A dramatic, romance-holo-vid-worthy exhalation that fluttered the papers on her desk.
Kate's pen stilled mid-signature, leaving an ink blot on the requisition form for plasma rifles. "For God's sake, Rebecca," she snapped, the sharpness in her tone making two passing aides quicken their steps, "we're not—"
"—dating, yes, I know," Rebecca interrupted with the weary patience of someone who'd heard this protest too many times to believe it. She adjusted her headset with deliberate casualness. "It's just... you two would be so good together. Everyone thinks so." Kate massaged her temples, counting to five in three different alien languages.
"Define 'everyone.'" Rebecca's fingers flew across her tablet before spinning it to face Kate. The screen displayed a live-updating spreadsheet titled "UNIT Relationship Probability Matrix," complete with:
- Departmental breakdowns
- Confidence intervals
- A disturbingly accurate recreation of their work schedules
- An entire tab dedicated to "Scarf Analysis" (Osgood's, apparently)
Kate closed her eyes and briefly considered the merits of voluntary reassignment to Antarctica.
++
The breaking point came at 1500 hours during the weekly security briefing. Colonel Ahmed, a decorated veteran who'd stared down Daleks without blinking, slid a report across the table with casual ease. "Your better half already signed off on the temporal readings," he remarked, as if commenting on the weather.
The resulting silence was so profound it could have preserved biological specimens for centuries. Across the table, Major Singh choked on his tea while three junior officers developed sudden intense interest in their data pads. Kate's smile could have flash-frozen a supernova.
That evening found Kate storming into Osgood's private lab with enough force to scatter a cluster of eavesdropping technicians. Their hastily abandoned coffee cups and surveillance equipment suggested they'd been stationed there for some time. "We need to talk," Kate announced, her voice slicing through the hum of equipment.
Osgood took one look at Kate's expression—a particular blend of fury and exhaustion she'd last seen during the Zygon negotiations—and wordlessly activated the lab's privacy protocols. The reinforced blast doors sealed with a satisfying thud, followed by the distinctive whine of audio dampeners engaging. The red lockdown lights cast everything in a faint crimson glow. "They've gone completely mad," Kate declared, pacing between workstations like a caged panther. Her heels clicked sharply against the polished floor. "I just had Communications ask if we wanted joint security clearance! Apparently, there's a 'couples discount' for biometric scanning upgrades." Osgood fiddled with her inhaler, the familiar weight a grounding presence.
"Engineering sent me a mock-up for co-branded lab coats yesterday," she admitted. "Our names embroidered in a heart over the pocket. They even included a sample of your favourite tea blend in the 'product testing package.'"
They stared at each other in horrified understanding, the reality of their situation settling like radioactive fallout. The faint hum of Osgood's quantum computer array provided an eerie soundtrack to their predicament. “We have to stop this," Kate said, her voice low and dangerous.
"But how?" Osgood pushed up her glasses, the lenses flashing as she moved to lean against a workbench. "Our denials are only fuelling the speculation. According to Petrovich's data models—”
"Don't cite the data models to me," Kate groaned, running a hand through her already-dishevelled hair. "I've seen the betting pools. I know what we're up against."
A dangerous glint appeared in Kate's eye then—the same look she got when negotiating with hostile alien species. "Then we give them what they want." Osgood's pencil—a vintage NASA model she'd had since university—snapped between her fingers. Graphite dust scattered across her notes.
"I'm sorry?"
"Not actually," Kate clarified, leaning against the console with deceptive casualness. The glow of the monitors cast half her face in pale blue light. "But if we stage a very public, very convincing breakup..." Understanding dawned across Osgood's features.
"The rumours would stop because there'd be nothing left to speculate about," she finished, her scientific mind already analysing variables. "That's... actually brilliant in its simplicity."
"Of course it is," Kate said with a smirk that didn't quite reach her eyes. Then she hesitated, an uncharacteristic flicker of uncertainty crossing her features. "Though it would require some... convincing performances from both of us." Osgood felt her ears grow warm beneath her scarf. The lab's climate control suddenly seemed inadequate.
"Right. Yes. Professional deception. For science."
"For sanity," Kate corrected, pushing off from the console. "And possibly the continued functioning of this organization."
They spent the next hour plotting over tea—Kate pacing while Osgood sketched scenarios on her tablet. Their heads bent close together as they debated optimal locations (high visibility), witness selection (maximum gossip potential), and aftermath strategies (plausible avoidance patterns). Outside the lab, at least four different departments placed frantic calls to the betting pool, causing wild fluctuations in the odds.
As Kate left that night—ostensibly in a huff for the benefit of their unseen audience—Operation: Heartbreak was officially underway. The stage was set. Now they just had to sell the performance of a lifetime.