AI Harlow took the iron stairs two at a time, breath a thin ghost in the chill . The old platform opened beneath her in a curve of shadow and soot, stalls like broken teeth lining the verge. Tarps hung slack. Glass jars caught the light of portable lamps, rows of dried roots and stoppered brown bottles, a chemist’s nightmare laid out under a city that never looked down here.
She checked her watch as if time could hold anything steady. The leather strap creaked on her wrist. She stepped under the tape and felt grit grind under her soles, old coal dust and something that stung the tongue, like metal and rain burned on a hot plate.
The body lay between two stalls, half on the white line that had once kept commuters civil. A man in his thirties, coat open, shirt stained dark. One shoe gone. Eyes fixed on the tunnel mouth like he’d died keeping count of the dark. A scattering of bone tokens sat near his hand, off-white discs carved with notches. They could have been milk teeth in that light.
Patel hunched near the torso, glove snapping back from his wrist. He lifted a corner of the coat with two fingers. Blue nitrile pinched. A uniform held a torch over them, arm already trembling.
Mugging gone wrong, Harlow?
She crouched, weight on the balls of her feet, knees brushing grit. The wound sat high on the left, in the meat under the collarbone. No bruising where fists had landed. No knuckle cuts. She skated her gaze over his hands. Clean palms, crescents of green under the nails.
It’s a market, Patel . If it were a mugging, we’d have nothing left to look at.
He shifted back on his haunches and pointed with his chin. Wallet in his inside pocket. Cash. No phone.
The stalls on her left still dripped with charms and tired glamour, thread knotted with copper, bundles of sage crushed flat, a box of iron nails that hadn’t seen a roof in a century. The right-hand stall had glass vials racked in wooden slots and a chalkboard that read Inks: Dragon’s Blood — Alder Sap — Night-Bloom Mix. The script looped elegant as a tattooist’s hand.
She ran a finger near the man’s throat, stopped at the nape. Sticky. She brought it up to her nose and took in something sour that didn’t bear a kitchen. Ozone, just a whisper . Burned air. The torch halo jittered.
Where’s the blood swipe, Patel ? If someone rifled him, there’d be transfer. Nothing smeared on the coat, nothing on the cuffs. Wallet sits like he put it there. See?
Patel sighed and took the wallet out to check again, hope stubborn in the gesture. Notes crisp. Driver’s licence sullen with a photo that belonged to another day. He put it back like he didn’t want to admit anything arranged itself too neatly.
Witnesses say two figures came up the service tunnel, argued, one ran. Then this one went down. That’s a mugging in my book.
Harlow stood and looked past him, past their reflection in a sheet of warped tin tacked as a stall wall. A circle had been drawn on the concrete between two oil spills. Someone had washed it away in a hurry. Chalk ghosted in the pores, a faint ring, gaps where dirt had been pushed with a wet rag. She stepped past the body and knelt again. The chalk’s edge broke at four points, angled slashes. Not an accidental boot scuff. A deliberate breach in a circle. Her mouth tightened.
You taking up art critique now?
She touched one of the slashes with a glove. The mark went west, clean and quick. Left-handed strike.
Someone broke their own circle and then this man obligingly fell dead into it? Patel rubbed his jaw. Come on.
She raised her head. The portable lamps cast islands of glare, the tunnels beyond pooled with old damp and the rasp of water moving in pipes. Beyond the far stall, a stack of crates had skid marks under them. Two long slides in the dust, leading nowhere. She walked there, left Patel to the forensics tech, and crouched again. The slides lay parallel, a hundred centimetres apart. Weight dragged. She placed her hand in one groove. The soot under her fingertips had a clean edge, as if a barrier had been there to catch fall. The crate stack top had a damp ring, an exact circle the size of a dinner plate. Her lips flattened.
Someone put something heavy on these, left it long enough to sweat, then lifted it straight off. And they didn’t wipe this.
Patel came up behind her, footsteps eager. He peered over her shoulder.
Looks like storage. These folks live in mess.
This mess had rhythm. Tarp cords tied with identical knots. A line of river stones placed along a stall edge at exact hand spans. Protective things. She squinted at a small brass disc half-slid under a torn paper bag near the drag marks. Verdigris caught the lamp and flared green. She hooked it with a pen and turned it into her palm.
A compass, small as a biscuit tin lid, casing rough with the kind of patina you couldn’t fake with vinegar. The face had fine etched sigils, notched along the rim. The needle didn’t sit north. It trembled and settled toward a bricked-up archway across the tracks.
She felt the tick of her watch as if it joined the needle in a conversation.
Patel reached to take it.
Don’t.
Her mouth clipped the word. She stepped back, lowered the compass into an evidence bag herself, the plastic crackling. The needle kept pointing through the bag toward the blocked arch. She held it flat, turned herself a slow quarter. The needle swung like a dog straining a lead, tried for the arch again.
Souvenir?
A tool.
For what, shopping?
She held the bag up so the torch lit the sigils. Not decorative. Protective. Old hand. The etching bled in three characters she had seen burned into Douglas Morris’s arm as he bled out in an alley off Kilburn High Road. Her throat went dry. She set that memory on a shelf and shut the door.
That arch has been bricked since ‘62. There is nothing on the other side; I checked that when we took the station. Patel ’s voice went schoolroom sure. He drew his coat closer against the cold.
Harlow walked to the arch. The brickwork wore graffiti like a second skin. A fresh line of white dust ran along the bottom row as if someone had sawed stone. She ran her gloved knuckles along it and grit came away. She stooped. At the heel of the arch, the dust had a clean triangle where a boot had pressed and then lifted, leaving the corner sharp. No other tracks approached the arch, though the soot at the base lay powder-soft.
Someone knew how to leave no prints in soot. Or they hadn’t walked at all.
She turned. The uniform with the torch shifted to keep up with her. His beam slashed the far wall and caught faces. A handful of market people stood at the edge of the tape, silent, hard as stones in a fast river. A woman with a black headscarf, a boy with a ring through his brow, a vendor with his grease-stained apron clenched in his fist like he could strangle it. And one face she recognised from a photo she’d taken on a long lens across the street from the Museum months ago.
Round glasses. Curly red hair frizzy from damp. Leather satchel too heavy for her shoulders. She tucked a coil of hair behind her left ear when Harlow’s gaze landed on her, a small defence she had probably learned the day she first fell into trouble and thought she could look harmless through it.
Eva Kowalski kept her feet planted. She let her eyes slide past Harlow to Patel and found nothing friendly there, then back to Harlow again, resigning herself to the harder face. Her freckles stood bright in the steel light.
This is a lawful scene. You don’t belong here.
I volunteer with archives when they clear old sites for saf— She caught herself, shut her mouth, regrouped. I heard shouting. I came to see if anyone needed help.
Your satchel looks heavy for mercy.
Books. You can weigh them if you want.
Harlow looked at the satchel strap digging into her coat. The bulge at the bottom could have been a book. Or a square of something older. The etched sigils on the compass still pressed through her skull.
You know what that is, don’t you?
Eva’s mouth quirked in a move that could have been a smile if it had found a friend.
A compass? My uncle had one above the mantel. Pointed at the dog. Broke sense of direction, in the family.
It points to doors. Her shoulders eased as she felt the truth fit into the space the Market left like a tooth pulled wrong. Not the street doors. Rift doors.
Patel let out a breath that steamed too heavy for the air. Come on, Quinn.
The Market moves. Every full moon. She kept her eyes on Eva. You don’t risk a fight on a night it moves unless you can hold it still. Or build your own way out.
Eva angled her chin as if the lamps felt bright. People sell cheap horror down here to scare tourists that never find the stairs. Full moons are for wolves in storybooks.
When is the full moon this month?
The faintest flinch, too quick for anyone not hungry for it. Three nights ago.
And yet the stalls weren’t half packed. She waved an arm. Herbs still strung. Vials still labelled. No crates at the platform lip waiting to be dragged out. Piles of bone tokens on a cloth like someone had expected customers till dawn. The Market hadn’t just failed to move. It had rooted.
The SOCO at the body called for a camera, voice clipped to keep temper quiet. Harlow walked back and watched as they turned the man to photograph the lividity. The pooling settled wrong. It spread backward into his shoulders more than a man on his back should show with his legs twisted to the right. He had gone down somewhere else. Maybe a metre. Maybe another room. The floor carried no drag marks. The body had arrived without touching the dirty part of the world.
Patel pointed at the blood. Big pool under him. Must have fallen fast.
And still not a drop on the soles of his remaining shoe. Harlow lifted the foot, the old tread bare to nothing. You run through your own blood and you carry it. His heel is clean. Check the other shoe when we find it.
A constable came up with a see-through evidence bag. Inside lay a scuffed loafer. The toe had a wedge of soot packed in, wedge too sharp for any alley. Harlow took the bag and turned it. The soot had a pattern like a notch. Like the points cut in the chalk circle on the floor.
Our left-handed friend breaks the circle, he goes down, he doesn’t hit the floor here. Harlow glanced at the arch again, felt the tick at her wrist. He hits somewhere colder. He comes here after.
Patel ’s shoulders rose to his ears. Quinn, don’t start with your rifts. We show this to the DI, he’s going to ask for a motive you can write on paper, not on rock with chalk.
She walked to a spill of thin salt that had lodged against a rail clip, crystals clear in a way that didn’t belong in a place like this. She pushed it with the edge of her boot. It slid like it had come from a clean jar, not a cook’s hand. Someone had poured a line in a hurry and misjudged the slope. Salt held space you couldn’t see. Most people knew that in their bones even if they never said it out loud.
She dug a finger gently in the slick on the dead man’s collar and brought up a smear. She rubbed it against the pad of her thumb. Grit ground. Not just blood. Fine grains. Salt.
She went back to Eva. Your books heavy enough to hold a door?
You’re reaching. Eva’s voice didn’t quite steady. This is Camden’s ghost town. Someone dodgy nicked drugs, someone else lost patience. Doors, compasses. Too much story.
You’ve worked in the Museum’s restricted stacks for two years. Harlow glanced at the satchel. You know what marks keep warnings from being warnings.
Eva folded her arms and tucked her left hand under her right elbow, hair catching again behind her ear.
The man with the headscarf apron called across the tape. We’re not your circus. That one wasn’t ours. He pointed at the body with his chin. He came with money and a terrible hat and the wrong questions. None of us would have taken a blade to him here. Not with the Market set like this.
Set how? Patel ’s patience snapped thin.
You hear the rails? The market folk went quiet. The vendor glanced at Eva, then at Harlow, and clammed.
Harlow closed her eyes and listened. The old station breathed. Water in pipes. Distant Vent. And then a sound she had tried not to listen for in three years—the faint tinny whine under hearing, like a knife on glass. Not the Tube. Not a thing with a timetable. Air rubbed thin. She opened her eyes and looked at the compass through the bag. The needle fought to hold the arch.
She crouched by the body again and took the hand. The green under the nails had lodged deep. Thick, crumbly. Not the bright finger-stain from a copper pipe, but the mossy green that ate old brass alive. She held her breath and used a swab, lifted a fleck. The patina on the compass casing matched it until you looked close. The compass had been wiped with oil. The flakes under the nails were dry, raw. He hadn’t handled the compass as a customer flipping a lid. He had clawed at the case or at another brass plate not present. He had fought for it.
She looked up at Patel .
Our victim handled something brass that wasn’t the compass. The compass has wipe marks, not scrapes. Look at the edge. Finely oiled. Someone made sure it looked clean and then tossed it so we’d stop with it. They wanted us to follow the needle and miss the real piece.
Patel rubbed his face.
What’s the real piece?
She pointed at the crates where the damp ring still clung like a ghost plate. Whatever sat there had weight . It changed the air. It kept the Market from taking the stairs on Monday. And it’s gone now.
You’re going to tell me it's a doorstop for a fairy door.
She held her voice even. The ring on the crate stacks is cold damp. Whatever was there came from somewhere colder than here and sat long enough to weep. And the salt at the rail clip isn’t kitchen coarse. It’s kiln-dried. Bagged for work. Whoever ran this brought kit, not knives.
The SOCO waved at her, two fingers sharp in the lamp light. He handed over a clear evidence bag with something square inside wrapped in cloth. He’d pulled it from under the body, folded flat.
Harlow eased the cloth apart. The corner showed brass, green eaten in vines. The edge had a notch just like the chalk breaks. She held it up and the compass in the other hand strained its needle even through the bag and the cloth toward the square of brass.
The colleague breathed out through his nose.
Nice. Now all we need is a legend.
Harlow looked to the arch. The Market folk stared through her or past her. Eva watched her, chin up, that worry under her jaw line like a tremor under tarmac.
Who moved the Market? Harlow’s voice didn’t reach far, but the words ran along the white line like a fuse. And why trap it here? Who needed this door anchored when it should have been somewhere under Whitechapel by now?
Patel threw up a hand. To hold a rave? To sell incense? To stab a man without cameras?
Harlow gestured at the ceiling. The soot above the body didn’t have the fan of an open flame. It had concentric ripples like heat pulsing from a fixed point, high and still. She looked at the brass square again, and the cloth under her fingers felt gritty where the green had dissolved.
He didn’t die in a mugging. She kept it flat, offered no ghost stories to fill his ears later. He died because he tried to pull something out of place. Or someone tried to shove him through it.
Eva shifted her satchel on her shoulder and looked at the arch like it might blink. The curl of hair slipped loose again behind her ear.
You’re going to rip that bricked mess up and find nothing but rats, Detective.
I’ll take rats.
Patel rolled his shoulders and glared at the Market folk. We’re not bringing a team to tunnel Camden because you found an antique shelf bracket, Quinn.
Harlow lifted the brass square higher, let the mask of cloth slip. The etched lines caught the lamp. Not a shelf bracket. Carved sigils matched the compass ring for ring. The same artisan’s hand. The kind that came out of a stall that did not take card.
She handed both to the SOCO and watched as he sealed them. Her watch ticked loud against her pulse . Eva chewed the inside of her cheek and didn’t look away.
Whoever brought that here knew what it did. Harlow turned to Patel . They moved with purpose. That’s the thing you missed.
He folded his arms, obstinate.
And the thing you missed, Quinn? He leaned in and dropped his voice so the others wouldn’t catch it. You always look for a door. You never look at the man bleeding on the floor.
She looked at the man. He had worn cheap aftershave and expensive shoes with a worn heel. The line of his jaw hadn’t shaved right. A plastic band impression lay pale on his finger, ring absent. She took in the small things like she could trade them for the one big thing she wanted. She had learned by now that bargains of that size never paid out.
He had come with money and questions and the wrong time of the month. She placed that in the table of their work and left it there.
Get the arch photographed. And the chalk residues. Full spectrum on the floor. Lift any salt. Harlow’s voice cut the air because it had to. And bag every bone token in that spread. People don’t bring cash and entry coins if they plan to leave by the stairs.
Eva pulled the satchel strap forward and crowded back behind the vendor in the headscarf as if he could make her smaller by proximity. Patel stared after her with something like annoyance and something Harlow didn’t name.
You want to pull her in?
Not yet.
We’re not running an occult unit, Quinn.
We’re running a murder inquiry. And a man didn’t bleed out because he stumbled into a bad queue for night-blooming ink.
She raised her eyes to the brick again. The compass needle twitched in its bag on the foldout table, tap-tapping the plastic like a trapped moth against a window. She let the noise thread into the station’s breath and tried to separate each sound, give each its place. Old rails. Bad air. Salt. Chalk. Blood. The metronome on her wrist.
Patel rubbed his face again, more gently this time.
If we go to the DI with doors and moons, he’ll laugh us out of Holborn.
We won’t go with moons. She nodded to the brass and the soot and the math of footsteps in dust. We’ll go with what we can count.
He followed her up to the foldout where the exhibits lined in tidy bags. He stared at the compass needle.)
How do you count that?
You don’t yet. You just don’t pretend it points north.