AI Detective Harlow Quinn ducked under the crumbling lintel and let the stale breath of the abandoned Tube station hit her full in the face. Old damp, rust, and something sharper beneath it, like burnt pennies rubbed into stone. Her boots found the edge of the platform, and her torch cut a pale strip across the tracks where weeds pushed through ballast like they owned the place.
A uniform waited by the taped-off stairwell, shoulders hunched in a high-vis jacket that looked too clean for the filth around it.
“Morning, Detective. You’re cleared to go down. They’ve got… people.”
Quinn’s jaw tightened. “What kind of people.”
The constable’s eyes slid to the darkness beyond the tape. “Not ours.”
Quinn stepped over the tape. The leather strap of her watch creaked as she checked the time out of habit, even though the station had no clocks left that worked. She kept her pace even, military in her bones. The stairs descended in a tight spiral, walls close enough to scrape knuckles. Someone had painted over old graffiti with a smear of black that still shone wet in places.
At the bottom, a line of portable work lights washed the platform in harsh white. The usual crime-scene detritus filled it: evidence markers, a folding table, plastic tubs. What didn’t belong sat between them—stalls made from salvaged doors, sheets hung like curtains, strings of charms that clicked and rattled when the air shifted.
The Veil Market.
Quinn’s nostrils flared. The place looked like someone had tried to build a bazaar out of a demolition site, then sprinkled it with theatre props. Bone wind chimes. Little jars full of cloudy liquid. A cage with nothing in it that still hummed like a live wire.
A man in a suit stood by the nearest light, hands on hips, looking offended by the architecture. DS Callum Reed. Good on paperwork, careless with his tone.
“Quinn. Finally. You picked a cracking day for a field trip.”
Quinn kept moving, eyes scanning . “Brief.”
Reed jerked his chin toward the centre of the platform. “Body’s there. Male. No ID. No phone. No wallet. And before you ask, no, we’re not calling it a ritual. He got stabbed. People stab people. It happens.”
Quinn’s gaze snagged on the chalky arc around the body, not police chalk. It looked like powdered limestone poured in a deliberate curve. Someone had stepped over it, and the powder had stuck to a boot tread, leaving a pale crescent on the concrete.
She crouched near the edge without crossing the line. “Who drew that.”
Reed scoffed. “One of the market lot, I expect. There were half a dozen of them loitering when uniforms found it. They scattered like pigeons when we showed badges.”
“Uniforms found it how.”
“A noise complaint. Camden council got a call about ‘screaming under the high street’.” Reed’s mouth twisted. “Like that makes sense.”
Quinn let her torch play over the body. The man lay on his back, arms splayed. Someone had closed his eyes, but not with care. Lids sat crooked. A thin line marked his throat, too neat for a struggle, but the blood didn’t spread like blood should. It clung in a glossy ribbon, as if the air had kept it from sinking into cloth.
Quinn leaned closer. “Where’s the pooling.”
Reed exhaled through his teeth. “Forensics bagged it. There was blood. Just… not much.”
Quinn’s fingers hovered over the concrete near the man’s head. The surface looked cleaner there, as if someone had scrubbed it and failed. A faint sheen caught in the light, like oil. She sniffed without touching.
No iron. No copper tang. Just that sharpness she’d noticed upstairs.
“Who’s the SOCO?”
Reed pointed. “Mills.”
A woman in a paper suit looked up from her kit, eyes tired above her mask. Mills had a steady pair of hands and the patience of a saint, but the station’s air seemed to push on her shoulders.
Quinn walked over. “What did you get.”
Mills held up a swab tube. “Minimal blood trace. That’s the thing. The incision went deep—windpipe, probably the jugular—yet the volume on the scene doesn’t match. Clothes absorbed some, but not enough.”
Reed wandered over, rocking on his heels. “He could’ve been killed elsewhere.”
Quinn looked at the man again. The back of his coat lay flat, no grit embedded, no smears of dirt. If someone dragged him, the fabric would’ve picked up the platform’s filth. It stayed too clean.
“His shoes?”
Mills tapped a photo on a tablet. “Dry soles. No tube sludge. No track muck. Like he stepped down here and lay down.”
Reed snorted. “You lot love your drama.”
Quinn’s eyes tracked along the platform edge. Damp dripped from the ceiling in slow drops. Every surface held a film of grime except the arc of powder around the body and a narrow path leading to it, scuffed clean in places as if many feet had paced the same strip. The strip ran between two makeshift stalls.
“What were they selling.” Quinn nodded toward the stalls.
Reed lifted a shoulder. “Junk. Talismans. Fake potions. Same rubbish you get at any goth market, just… underground.”
Quinn walked the strip. The work lights threw hard shadows, turning the hanging charms into skeletal silhouettes. She paused at a table made from a door set on crates. A cloth covered it, embroidered with tiny symbols that looked like thorns . Someone had left a row of coins—old ones, foreign, worn almost smooth.
A small brass compass sat near the coins, half hidden under the edge of the cloth. Verdigris mottled its casing, and its face held etched sigils that didn’t match any map markings Quinn had seen. The needle jittered in tight, angry circles as if it couldn’t settle on north.
Quinn’s hand stopped short. “Bag that.”
Reed leaned in, frowning. “A compass? That’s your big break?”
Quinn kept her gaze on the needle. It spun, then jerked toward the far tunnel, the one sealed with corrugated metal. It held there, quivering.
Mills stepped closer. “I didn’t log that. That wasn’t on the body.”
Quinn’s eyes flicked to the cloth, the coins, the empty space where other items had been removed . “Someone cleared this stall in a hurry. Left the compass.”
Reed folded his arms. “Or a tramp nicked the rest and couldn’t flog a broken compass.”
Quinn reached for gloves, snapped them on, then lifted the compass with two fingers. It felt warm, like it had sat in a pocket. The sigils caught the light and seemed to drink it.
She held it away from her body, steady, and walked a few paces. The needle pulled, stubborn, always toward the sealed tunnel.
Quinn lowered it and looked at the tunnel. The metal sheet bore dents from old kicks, the bolts rusted. A smear of that same oily sheen marked the floor near it, but it didn’t spread like oil. It sat in a shape too deliberate, a crescent, like someone had dragged the edge of a coat through it.
Reed followed her look . “That tunnel’s dead. It’s been sealed since—Christ, before I joined.”
Quinn crouched and angled her torch. The concrete held a faint pattern, almost invisible until the light hit it: shallow scratches in a circle, interlocked lines inside. Not random scuffs. Someone had scored the floor with a tool.
A memory rose, uninvited: DS Morris lying on wet pavement, eyes open, rain on his lashes. No blood where there should’ve been. Quinn’s grip tightened on the compass until the brass bit her glove.
Reed watched her face. “You alright?”
Quinn stood. “Get me the first officer.”
Reed glanced back at the stairwell, then waved a uniform over. The constable approached with a notepad already open, face pale under the work lights.
“Constable. Walk me through exactly what you saw.”
The young man swallowed. “Me and Haines responded to the call. We found the entrance open—someone had shifted boards at street level. We came down, heard voices. Not English at first. Then quiet. We reached the platform and saw… all these stalls. Like a market, but closed. Then we saw the bloke on the ground. No one near him.”
Quinn’s eyes stayed on his hands. They shook, small tremors. “You touched anything.”
His ears reddened. “No, ma’am.”
Reed’s mouth pinched. Quinn didn’t let it go.
“You moved something.”
The constable’s throat bobbed. “Haines… Haines kicked a thing by the body. Thought it was a knife.”
“What thing.”
He looked down, ashamed. “It was a token. Like… a bit of bone carved into a coin shape. Had a hole drilled through. It was by his fingers. Haines nudged it, and it slid under his hand. Then Mills told us to back off.”
Quinn’s head tilted. “Where’s the token.”
Mills turned away from her kit and pulled a small evidence bag from a tray. Inside sat a pale disc, carved with tiny notches. It looked like a vertebra slice cleaned too well.
“Entry requirement,” Quinn muttered without meaning to.
Reed blinked. “What was that.”
Quinn ignored him and held up the compass again. The needle still strained toward the sealed tunnel. She moved closer to the body, careful not to cross the powder arc, and watched the needle’s behaviour.
It calmed. Not fully still, but it stopped spinning . It pointed past the corpse, past the circle scratched into the floor, right at the metal barrier.
Mills shifted, unease in the way she held her shoulders. “Detective, I thought compasses pointed north.”
Quinn lowered it. “This one doesn’t.”
Reed rubbed his forehead. “You’re not seriously putting that in your report.”
Quinn looked at him. “You’ve got a body with a wound that should’ve emptied him. No drag marks. Shoes clean. Blood missing. And a scratched circle by a sealed tunnel in an illegal market under Camden. You want me to write ‘standard stabbing’.”
Reed’s jaw worked. “I want you to write what you can prove.”
Quinn walked the perimeter of the powder arc. The limestone dust lay thick in some areas, thin in others. A shoe print broke the line at one point, but the break looked old, dust compacted by multiple steps. Someone had crossed there over and over. A frequent path.
She stopped near the corpse’s right hand. The fingers curled slightly , not clenched, but posed . A smear marked the concrete under the fingertips: the same oily sheen, but here it held a faint ridge, like something had been pressed and lifted.
Quinn crouched and angled her torch low. Tiny flecks glittered in the smear. Not glass. Not sand. They caught the light and flashed cold, like powdered metal.
Mills leaned closer, eyes narrowing. “That wasn’t in my sweep.”
Quinn’s gloved finger pointed without touching. “Swab that. And photograph it again with oblique light.”
Mills moved at once, snapping new photos.
Reed crouched too, impatience leaking into his posture. “That’s just residue. He could’ve handled a tool.”
Quinn shifted her torch to the man’s wrist. A tan line circled it where a watch had sat. Skin looked clean there, but a faint bruise hugged the bone on the inside, an oval mark like someone had gripped him hard.
Quinn’s eyes traced from the bruise to the powder line, to the scratched circle, to the sealed tunnel. Her mouth went dry.
Reed watched her again. “You’re doing that thing. The stare. You’ve got something.”
Quinn rose and walked to the sealed barrier. The corrugated sheet held a crude padlock, but the lock hung open, clasped around nothing. Someone had opened it, then placed it back as camouflage.
She knelt and ran her torch along the bottom edge. The sheet didn’t meet the ground flush. A gap ran along one side, wide enough for fingers.
Quinn pressed her glove to the floor near the gap. The concrete felt colder there than the surrounding slab, cold that climbed her knuckles through latex. Her breath fogged in front of her mouth.
Reed shifted his weight . “Don’t tell me you feel a draft. It’s a tunnel.”
Quinn slid her fingers under the edge of the metal and lifted. It scraped, loud in the empty station. A gust rolled out, not air but a stink like wet pennies and burnt stone.
Mills pulled her mask tighter. “Jesus.”
Quinn held the sheet up just enough to shine her torch through. The beam cut into darkness, then snagged on something that shouldn’t have sat in a disused tunnel: a second chalk circle, cleaner than the first, painted on the tunnel floor in a pale substance that reflected back at the light. It formed an almost perfect ring, and in its centre sat a smear of black that didn’t look like soot. It looked like a shadow left behind after an object moved.
The compass needle in Quinn’s other hand snapped toward it and held so hard the brass casing trembled .
Reed’s voice dropped, the first hint of caution. “What the hell is that.”
Quinn didn’t answer. She watched the edges of the black smear. The darkness didn’t sit still. It rippled, thin as oil on water, and the air around it bent the torch beam, warping the light into a faint curve.
Mills spoke from behind her shoulder, words careful. “Detective… that’s not a stain.”
Quinn eased the metal sheet higher and leaned closer, keeping her body outside the tunnel. The cold pressed harder against her face, and the smell thickened, filling her throat. Her eyes watered, but she kept them open.
A faint line ran from the chalk ring toward the platform, like a trail drawn by a dragged object. The line ended at the corpse.
Quinn looked back at the body, then at the chalk, then at the compass.
Reed crouched beside her, his earlier certainty gone from his posture. “So he didn’t get stabbed for his wallet.”
Quinn’s gloved hand tightened on the compass until the sigils bit into the latex.
“Call this in,” she murmured, eyes fixed on the warped air inside the ring .
Reed’s face twisted. “Call it in as what.”
Quinn held the metal sheet with one hand and kept the torch steady with the other, the beam shaking in the bent air.
“As a crime scene that doesn’t fit any crime I’ve ever worked,” her voice scraped out, “and as a tunnel nobody should go into.”