AI The constable at the alley mouth lifted the tape with a gloved hand.
"You're late, ma'am. Trains are on time and you're not. End of days."
Harlow ducked under, rain sliding off the brim of her hood. The alley behind Camden High Street narrowed between two brick walls tattooed in neon paint and old band posters. A metal service door yawned open halfway down, frame buckled as if kicked by something with patience rather than force.
"Scene secure?" Her voice bounced off wet brick.
"Best we could." The constable shifted on his feet. "Station's shut since the seventies. One stairwell in, one emergency exit we blocked. SOCO's still grumbling about the mould."
Harlow checked her watch . The leather strap had worn down to pale threads near the buckle. 03:17 glowed in tired green. She swept the alley with a slow look, then moved through the door.
The air changed on the first step. London throbbed faint on the other side of the brick, bass from a club, traffic wash. Down here, the sound dropped, thick and close, as if the dark pressed cotton into ears. Rust bloomed along the handrail. Old posters flaked down the stairwell walls: a grinning woman in a swimsuit urged people to see Britain by Rail. Someone had graffitied horns on her and blacked her eyes.
Boots clanged on metal treads ahead.
"Quinn. About bloody time."
Reed leaned over the rail a flight below, face washed in the blue spill from his phone. His tie hung loose, grey shirt creased into fatigue lines.
"Path got lost," she stepped down past him . "What have you dragged me out to admire?"
"You'll see." He tucked the phone away . "Unidentified male, probably twenties. No ID. One of the workmen went down the wrong tunnel, found him on the platform. Freaked the lot of them. They thought it was urban explorers, at first."
"Urban explorers don't usually leave bodies."
"Depends how urban."
The last flight opened onto the platform. Floodlights on tripods threw harsh pools across cracked tiles and flaking paint. The old Camden Northbound sign sagged over empty tracks shrouded in shadow. A smell ran under everything: damp concrete, old oil, something metallic that clung to the back of the throat.
SOCOs moved in their paper suits, tape stretched around a wide portion of the platform. The body lay near the centre of that taped square. White scene markers dotted the ground like low teeth.
"Watch your step." Reed walked her toward the tape. "You'll ruin my whole theory if you smudge something."
"You have a theory?"
"Oh, several. All more interesting than paperwork."
Harlow paused at the tape. The victim lay on his back, arms splayed, palms up. Dark hair curled damp against his forehead. No obvious wounds. His mouth hung open, teeth bared in a way that belonged to shouting, not peace. His eyes stared at the tunnel ceiling.
"Overdose?" She kept her tone flat .
"That's the early favourite." Reed scratched his jaw. "Cold down here, you know. Lad shoots up in an abandoned station, no one finds him till weeks later. Except he's fresh as a daisy, so timing's off, but still."
"No syringe."
"Could have rolled onto the tracks. SOCO's checking. No track marks on the arms, though. Or legs. Might be wrap or pills."
Harlow stepped inside the tape. The nearest SOCO nodded and shifted to give her room.
"Careful of the chalk, guv."
She looked down.
A circle ringed the body, drawn in off-white lines on the old tile. Not smooth. No neat compass sweep. The line kinked at points where the chalk stub had caught in tile cracks, then pressed on. Inner marks branched from the main ring, looping in repeated patterns. Repeated, not random. No smudges where a foot had dragged through.
Harlow crouched, joints protesting. The chalk under the victim's hand lay whole, not crushed. He lay just inside the circle, heels almost touching the line. The toe of his right trainer pointed toward the tunnel mouth.
"Kids," Reed shrugged behind her. "Cult nonsense. Draw a few pentagrams, drink cheap vodka, scare each other. One goes too far."
"None of these are pentagrams."
"Fine. Emo sudoku."
Harlow ignored him. The chalk line didn't break under the body. It faded where his weight pressed, but the curve remained. Someone marked the circle first. Then he went inside.
"Any sign of a camp?" She traced a finger above the chalk, not touching. "Sleeping bags. Bottles. Cigarette ends."
"Nothing. Just him." Reed shifted again. He never stayed still at scenes. "No drag marks, no other footprints except the workman's. We're on old tile, so prints aren't generous, but still. You know the drill."
The floodlights hummed. Water dripped somewhere into stillness.
She leaned over the victim. No needle. No wrap. His shirt lay rumpled, top button gone. Black singe ringed the empty buttonhole, the fabric edges crisped. The same dark ring rimmed his nostrils, not dirt, not blood. Inside his nostrils, skin darkened as if hollowed by smoke.
"Any burns?" She angled her head to catch better light.
"That's the odd bit." Reed knelt next to her. "No external burns on the skin. None. Just that." He pointed at the buttonhole . "And those."
He meant the eyes. The sclera had clouded to a milky grey. Fine spider-webbed fractures ran from the pupils outward, like frozen lightning. No petechial haemorrhages. Something else.
"Pathologist?"
"On their way. You know how they love early mornings."
She reached into the inside pocket of her coat. Fingers closed around cool metal, smooth except for faint etching under the skin. For a breath she stood still, hand there. The familiar weight steadied her, then reminded her what kind of scene this might be.
She drew out the small brass compass.
Reed's eyebrows went up.
"You bringing orienteering back into fashion?"
"Picked it up on the Holborn job." She cupped it so the etched sigils on the face stayed turned toward her, away from Reed. "Thought I'd see if we can navigate our way out of your theories."
He snorted.
She flipped the lid. The glass showed faint scratches. Verdigris crept along the casing edges like dried moss. The needle jerked once, then spun, faster than it should, blurring into a dark circle.
Reed leaned closer.
"Bit eager for north, isn't it?"
"It's old." She angled it in her palm. The needle slowed, then snapped, hard, not toward the tunnel mouth, not along the platform, but at the wall behind the victim's head .
A glossy advert from some forgotten year peeled there, corners curled. A woman laughed over a breakfast table, all teeth, blocked by mould blooms where damp had crept in.
Harlow closed the lid.
"Electromagnetics from the track," Reed stretched his back. "Or your toy's knackered."
"Tracks are dead."
"Still metal. Still the earth doing its thing."
"Compass points at the wall, not the rails."
"Maybe the wall's special."
The metallic taste in her mouth thickened. She swallowed it down.
"Scene log?" Her gaze flicked to the small table near the stairwell, the clipboard anchored under a stone. "Who's been down here?"
"Workman, you, me, SOCO team, two uniforms. No one else. We cleared the tunnels first, in case we had a live knifer hiding."
"You disturb anything before calling me?"
"Just your sleep."
She studied his face. Lines cut deeper around his mouth than last year. Tiredness, not deceit.
"I want any bodycam footage from the first officers, now."
"They're uploading."
Her eyes went back to the victim. The soles of his trainers bore a fine dust, darker than the platform grime. Not track grease. Something granular.
She reached for an evidence tech's attention.
"Prints off his shoes yet?"
"Working on it, ma'am." The tech glanced up. "We dusted the soles. There's a residue we don't recognise. Already bagged a sample."
"Let me see."
The tech passed her a clear swab tube. Inside, faint black grain clung to the cotton tip. Not soil. Not soot. More like ground charcoal pressed with something oily.
Reed watched.
"Someone needs to clean their boots."
"This station's been shut forty years." Harlow turned the tube in her fingers. "Where's he walked through that's dirtier than this?"
"Have you seen the upstairs gents on the High Street?"
She opened the victim's hand with a gloved grip. The fingers lay stiff, not fully rigid. Under the nails, the same black residue packed tight. Scratches marked his palms, thin crescents.
"He grabbed something. Or clawed at it." She looked up. "Any sign of whatever that was? Rope, cable, wood, wall?"
"Nothing obvious. We checked around for loose hardware. The rail company wants to know if we nick anything, so they were keen on an inventory."
Her fingers slid into his jacket pocket. Wallet absent. Phone absent. She found keys – two standard yale, one heavy old thing that belonged on a cellar door – and something that clicked faint against her glove.
She drew it out.
The token lay on her palm, small enough to vanish in a child's hand. Bone, bleached to a dull cream, surface polished by touch. A hole pierced one end, as if for a cord. On one side, a symbol had been carved shallow, then inked once in black that had sunk deep; a vertical line crossed by three horizontals, not quite even . On the other, a familiar spider-crack pattern radiated from the hole. It didn't spread; it sat, contained, as if someone had frozen the moment something tried to split it.
Reed leaned closer.
"Oyster card's had a rebrand."
"You recognise this symbol?" She turned it so he could see the inked mark.
"Looks like a music festival logo. Or one of those brands that sells expensive water in glass instead of plastic."
"Anything like it on his clothes? Bag? Jewellery?"
"Nothing. We searched. No other personal effects."
The token's weight felt wrong for bone, heavier, denser. Her thumb ran along its edge. Heat lingered there, faint, like a stone that had sat in sun. There was no sun down here.
"Bag it."
Reed raised both hands.
"Your show."
The SOCO slipped an evidence bag open. Harlow dropped the token in, watched it flash once under fluorescent light before plastic fogged the edges.
"Harlow." Reed rested a hand on his own belt, fingers tapping out a rhythm he hadn't noticed. "We're calling this what? Suspicious death until the doc tells us otherwise. I'm all for keeping an open mind, but we've got one unidentified lad in an abandoned station with no visible wounds, no ID, and some art students' scrawl on the floor. Occam's razor loves heroin."
"Occam never worked Camden nights."
"You know what I mean."
She walked the edge of the chalk circle, eyes on the line. No footprints broke the dust along its path. Chalk had fallen thick at two points, where someone had paused or pressed harder. Each of the inner marks repeated at precise intervals. Too even for drunk kids bored on a Friday.
She pointed at one.
"You think art students do this freehand, in the dark? No smears. No corrections."
"Some people like rulers."
"The circle sits off-centre." She stepped back, measuring with her gaze. "Not aligned with the tiles or the platform edge. Whoever drew this didn't care about symmetry of the station. They cared about something else."
"Like what?"
"The tunnel."
She stood at the victim's head. From here, his feet pointed straight at the tunnel mouth. The circle's forward-most point touched the yellow safety line by a hair. Behind his head, less than a foot from the outer edge of the chalk, the breakfast advert peeled. A faint, almost unnoticeable draught whispered from its lower corner, where the paper had curled away from the wall.
"Draught." Reed frowned. "Ventilation."
"From where?" She pressed the loose corner with one gloved finger. The paper crackled. Cold air slid out, sharper than the heavy damp that filled the station.
"Old maintenance shaft? Rats need fresh air too."
"Rats don't draw circles."
She peeled the advert higher. Behind it, the wall didn't show painted brick. Someone had tiled this patch differently, smooth pale slabs set tight, edges marked by dark lines. Not grout. Something more deliberate. Tiny sigils ran along the seams, etched so small they almost vanished into grime.
She held her breath.
The same sigils adorned the face of the compass in her pocket. The same hand, or the same tradition.
Her fingers itched to pull the compass out again. She kept them still.
"You thinking what, hidden room? More trainspotters' heaven?" Reed peered past her shoulder. "We can get the council to send a survey team. Not before breakfast, mind."
"Don't touch it yet." Her tone came out sharper than intended.
He glanced at her, caught something in her expression, stepped back a half-pace.
"You see a hidden stash of paperwork in there, it's all yours."
The hum of the floodlights pressed in. Somewhere, a far train rumbled, not on these tracks, but above, running on modern lines . Vibration bled down the pillars, faint tremor through her boots. Dust fell in lazy skeins from the ceiling.
She ran through the picture in her mind.
An abandoned station with one easy access from a public alley. No CCTV on the approach; cameras up there either broken years ago or aimed elsewhere. A circle drawn with care and purpose, not vandalism. A young man with hands torn by something rough, dust from somewhere deeper than this station packed under his nails and ground into his soles. A token from a world no one on Reed's team knew, sitting in his pocket like a ticket he never got to use.
"Bodycams," she reminded.
Reed lifted his radio.
"Control, DI Reed. Pull first response footage from the Camden North disused station job. Priority. Straight to DI Quinn's inbox and mine. And I want environmental overviews, not just the corpse."
Static crackled back, then acknowledgement.
Harlow stepped away from the chalk, toward the platform edge. She knelt, peered down. The track bed lay quiet, rails mottled with rust. No fresh scuffs, no dropped paraphernalia. No syringe glint . No knife. Nothing.
"Could have come in through the tunnel?" Reed joined her, gaze trailing off into the dark. "Other stations connect somewhere along the line. Kids get down from live platforms all the time."
"Where are their footprints?" She pointed at the layer of dust near the first set of sleepers. "No disturbance. Just pigeon droppings and time."
"Could be he came hours earlier. Dust settles."
"Not that fast."
He worked his jaw.
"All right. So he comes in your special door, stands in your special circle, clutches a mystery token, and dies of nothing we can see. What's your interpretation, then?"
Harlow watched the body for a long moment. The fractures in his eyes caught the light, tiny mirrored branches.
"This isn't an overdose," her voice carried across the tiled vault. "Someone used this place for something. It went wrong. Or right, depending on what they wanted."
Reed folded his arms.
"You planning to write 'something' on the incident report?"
"We'll start with 'unlawful killing' and work from there."
"You really think it's a murder?"
"The chalk's not for decoration. Neither is that wall." She nodded toward the hidden tiles. "People brought him here. They prepared this."
"You don't know that."
Her jaw tightened.
"I've seen it before."
Reed's attention sharpened.
"You talking Morris?"
She didn't answer. The memory of another basement, another circle carved instead of chalked, another partner's hand slack in hers, rose quick and hot. The same smell of metal in the air. The same wrong quiet after.
She pushed it down.
"We're not losing this one into a coroner's tick-box," she looked back at the token bagged on the table. "Get me a list of every crew with authorised access to disused lines within five miles. And every trespass incident report down here for the last year."
"That's a lot of paper."
"Then start turning it." Her gaze returned to the circle. "Everyone else might see an accident. I don't."
Reed blew out a breath.
"Fine. You call it suspicious, we dance the dance . But if the doc comes back with a heart defect and I lose my Saturday on ritual-cap nonsense, you buy the first round."
"Deal."
She slipped the compass back into her pocket. The metal throbbed faint against her palm, needle pushing insistently toward the wall behind the peeling advert.
Harlow walked back into the circle's edge, toes a breath from white chalk, and looked down at the young man, the careful ring around him, the cracked eyes that reflected light he would never see again.
"Start from here," her voice cut through the hum. "Everyone looked at the body. Start looking at who went to this much trouble to make sure it ended up in the wrong place."