Chapter Text
221B Baker Street was quiet in the way only London could manage - an expectant, humming sort of quiet, like the city was holding its breath between sirens. Outside, evening rain pressed gently against the windows, turning the streetlamps into vague, amber ghosts. Inside, the living room was dim, the lamps set low, shadows softened by the warmth of an overused kettle and the smell of gun oil.
John sat in his armchair, one ankle crossed over the other, drifting somewhere between thought and the numb fog that often replaced it. He wasn’t tired, not exactly. Tiredness implied a capacity for rest. He’d misplaced that months ago. Instead he existed in that peculiar, stretched-thin state of wakefulness, mind hovering like a needle wavering above empty vinyl grooves.
Across from him, Sherlock reclined - well, attempted to recline - on the sofa. His long limbs were arranged with precision rather than relaxation, as though he’d calculated the exact angle required to look unbothered. It wasn’t working. It never did. Sherlock Holmes at repose still buzzed faintly with electricity, all sharp edges and restless synapses, the human equivalent of an overclocked engine pretending to idle.
He was staring at the ceiling, brow creased in a way John recognised instantly.
“You’re thinking too loudly,” John murmured.
Sherlock didn’t look over. “You’re projecting.”
John huffed, a soft, weary sound. “You’re vibrating like a mobile phone trapped between sofa cushions.”
“That’s physically impossible. A mobile phone vibrates at-”
“You know what I mean.”
Sherlock’s silence was a tacit admission.
The flat settled again. The clock on the mantel ticked with deliberate, insolent clarity. Rain tapped at the windowpanes. Somewhere downstairs in 221A, a dish clattered.
And then-three rapid knocks.
Sharp. Urgent. Wrong. The kind of knock that arrived hours after midnight or seconds before disaster.
Sherlock sat up instantly, the motion fluid, predatory.
“Desperation,” he said under his breath.
“Possibly fear. Heavy knuckles. Middle-aged, perhaps older. The pace suggests agitation, not aggression-”
“Or,” John interrupted, standing, “it’s someone who’s cold, wet, and really wants to come inside.”
Sherlock made a noise like he was considering disputing this, then dismissed the notion as beneath him.
John reached the stairs first.
When he opened the door, the corridor revealed a person who appeared to be constructed entirely of frayed nerves and damp wool. A man; late thirties, perhaps - stood wild-eyed and panting, hair plastered to his forehead in rain soaked disarray. His coat was several sizes too small or he was several problems too large; either could be true.
“Are… are you Sherlock Holmes?” he stammered, gaze flicking between John and the staircase behind him.
John opened his mouth to reply, but the stranger barreled on.
“I’m not mad,” he said desperately, which was precisely what someone mad might say. “Or- well… I might be, but not about this. I saw something. Something I shouldn’t have. Something impossible.”
Sherlock appeared behind John with the disconcerting swiftness of a summoned apparition. “Impossible,” he repeated, savouring the word. “Do come in.”
The man stumbled inside, dripping onto the floorboards with anxious enthusiasm. John shut the door behind him.
Upstairs, Sherlock gestured the stranger into the living room with the air of a conductor cueing an orchestra. The man perched on the edge of a chair, hands twisting in his lap.
“What’s your name?” John asked, voice steady, the doctor in him surfacing.
“Colin,” the man said. “Colin Marsh.”
“And what exactly did you see, Mr Marsh?” Sherlock asked, leaning forward, elbows on knees, eyes bright and hungry.
Colin swallowed. His throat bobbed. “A box.”
“Many exist,” Sherlock said. “You’ll have to be more specific.”
“A-” Colin hesitated, as though the words themselves were absurd. “A telephone box.”
“Still many exist.”
“It was… blue.”
Sherlock froze. Just marginally. But John noticed, of course he noticed.
Colin’s voice dropped to a whisper. “It wasn’t just blue. It… it appeared, right there on Tenterfield Lane. Just - materialised. And there was this sound, like… like metal scraping across the sky. Like the world was dragging something behind it.”
John felt something shift in the air.
Sherlock’s eyes darkened with interest. “And then?”
“And then,” Colin whispered, “a man stepped out. Tall. Coat flapping in the wind though the air was still. He looked at me like… like he knew me. Or like he knew what I’d do next. And then he smiled. This impossible, tired smile. And he said, ‘Wrong lane, right time,’ and then he went back inside and the box just-”
He mimed an explosion outward with his fingers. “-vanished.”
Silence. Heavy. Expectant.
John exhaled slowly. “Sherlock..”
But Sherlock was already standing. Already moving. Already burning with purpose.
“John, get your coat.”
“What? Why?”
Sherlock turned to him, and in his eyes, usually so precise, so razor-sharp, there flickered something strange. Something like recognition. Or memory. Or dread.
“Because,” Sherlock said softly, “someone has arrived in London. And he shouldn’t be here.”
Colin blinked. “You…you believe me?”
Sherlock didn’t look at him. His gaze remained on John, steady and unsettling.
“I don’t believe in the impossible, Mr Marsh. Only in the improbable. And this…” He inhaled once, sharply. “This is very, very improbable.”
John grabbed his coat.
Whatever was coming- they’d faced strange things before. But this felt different. Like the air before a storm.
As they stepped out into the rain-chilled night, John glanced at Sherlock.
“You’ve seen something like this before,” he said quietly.
Sherlock didn’t deny it.
He only said, “No. But someone I once knew had.”
And with that, they disappeared into the street, rain washing the city clean around them, as somewhere in London, unseen, unheard—a familiar, impossible sound scraped across the sky.