AI The air in the abandoned Camden Tube station smelled of ozone, stagnant water, and ancient dust. Detective Harlow Quinn stepped off the rusted heavy-duty service ladder, her boots hitting the cracked concrete platform with military precision. She adjusted the worn leather watch on her left wrist out of pure habit. The dial read ten minutes past three in the morning.
She stood at five feet nine inches, her posture rigid as she surveyed the subterranean chaos. Arc lights set up by the forensics team threw harsh, unforgiving shadows against the filthy ceramic tiles. The illumination caught her closely cropped salt-and-pepper hair and highlighted the sharp jaw that was currently set in a grim rigid line. Eighteen years of decorated service with the Metropolitan Police had trained her to read a room before anyone even spoke to her. Right now, this room was screaming that something was fundamentally wrong.
Sergeant Miller, a heavy-set man with a flushed face, jogged over, ducking under a strip of yellow police tape.
"Glad you made it, Quinn," Miller said, wiping sweat from his forehead. "Though I'm not sure why the superintendent woke you up for a squatter dispute. Looks like a turf war. A bad one, but standard underground rot."
Harlow swept her dark brown eyes over the platform. Standard underground rot did not look like this. The platform was lined with the remnants of wooden stalls. Heavy velvet drapery, scorched by some localized flash of heat, hung rigidly from makeshift metal frames. It looked less like a homeless encampment and more like a bizarre, antiquated bazaar violently interrupted.
"Walk me through it, Miller," Harlow said, her voice a flat, calm baritone that demanded facts over assumptions.
"Victim is an unidentified male, late twenties," Miller pointed to a chalk outline surrounded by scattered debris near the edge of the old tracks. "Blunt force trauma, massive lacerations. We found a couple of broken bottles. I figure an illegal rave or a squatter market got out of hand. Two rival gangs fighting over the turf. We brought in a consultant to look at some of the graffiti they left behind. A historian."
Harlow stepped past Miller, moving toward the center of the platform. She ignored the crime scene photographers snapping pictures of the chalk outline and focused on the periphery. At the edge of the light, a young woman was crouching near a shattered wooden display table.
The woman was entirely out of place in a murder scene. She stood five foot four, dressed in an oversized tweed blazer. Her curly red hair tumbled over her shoulders. She wore round glasses that kept sliding down a freckled nose. A worn leather satchel full of books was slung cross-body over her chest, and she held it in a death grip.
Harlow approached. "You the consultant?"
The woman jumped, standing up quickly and turning. She possessed a distinctly nervous energy, her green eyes darting around the platform as if expecting the shadows to lunge at her . "Yes. Eva. Eva Kowalski."
Harlow gave her a slow, measured assessment. "Detective Harlow Quinn. Met Police."
Eva immediately reached up, tucking a stray curl of red hair behind her left ear. She cleared her throat. "I work as a research assistant at the British Museum. The restricted archives. Your department sent me photos of the symbols carved into the pillars here. They asked me to come down and identify them."
"And have you?" Harlow asked, her sharp jaw tightening .
"They appear to be derivative," Eva said, her voice wavering slightly . She tucked her hair behind her ear again. "Fake occultism. Probably teenagers copying things they saw in a video game. An illegal rave, just like your sergeant said. People setting up an underground club. It happens."
Harlow turned her attention away from the nervous academic and looked at the shattered table. Among the splintered wood and crushed glass vials lay a small object the forensics team had marked with a yellow plastic evidence tent. Harlow pulled a pair of latex gloves from her coat pocket, snapped them on, and lifted the object.
It was a small brass compass, heavy and cold in her palm. The casing had a thick patina of verdigris, mapping green chemical rot across the metal. Harlow rubbed her thumb over the face of it. The glass was cracked, but underneath, the metal face was intricately etched with protective sigils that matched the ones carved into the station pillars.
"Steampunk junk," Miller said, coming up behind them. "Kids leave it everywhere down here. Makes them feel edgy."
Harlow stared at the compass. Her mind flashed back three years. DS Morris, her partner, bleeding out in a rain-slicked alleyway in Soho, surrounded by impossible burn marks and symbols she could never decode. The brass in her hand felt exactly like the weird residue she had found on Morris's jacket. The department had written his death off as a gangland dispute. She had never believed it.
"No," Harlow said, her voice cutting through the damp air . "This is not steampunk junk. Look at the craftsmanship."
She turned the compass over, showing the back to Miller, then to Eva. "The hinges are practically seamless. The casing is solid. And look at the needle."
Harlow rotated the compass slowly in her palm. A normal compass needle would drag, attempting to reorient toward magnetic north. This needle did no such thing. It was locked solidly in place, pointing directly toward a pitch-black, bricked-up tunnel entrance at the far end of the station. She turned her body ninety degrees. The needle did not waver. It remained completely fixed toward the dark archway.
"Must be rusted shut," Miller offered with a shrug.
"Brass doesn't rust, Sergeant," Harlow said coldly . "And the pin inside is seated perfectly . It's pointing exactly where it wants to point."
She looked at Eva. The young woman had gone noticeably pale beneath her freckled complexion. Her knuckles were white where she gripped the strap of her worn leather satchel. She was holding her breath.
"Tell me, Ms. Kowalski," Harlow said, taking a step toward the historian. "If this is an illegal rave, where are the glow sticks? Where are the discarded nitrous oxide canisters? The beer cans?"
"I wouldn't know," Eva stammered, tucking her hair behind her left ear for the third time in two minutes.
Harlow pivoted, pacing down the length of the ruined stalls. "You don't set up heavy velvet drapes and solid table displays for a rave. You set them up for trade. This was a market. An organized, lucrative market."
Harlow reached the base of the metal stairs leading to the upper concourse. She knelt down and pointed to another yellow evidence tent. "Miller, what did forensics catalog here?"
"A piece of debris," Miller said, checking his notebook. "Looks like a fragment of bone. Animal, probably. A dog got down here at some point."
Harlow picked up the bagged object. It was a smooth, polished piece of bone, flat and wide, drilled with a single hole in the center. An entry token.
"A rave or a squatter camp is an open door," Harlow said, standing back up and addressing them both. "You wander in, you wander out. But this?" She held up the bagged bone token. "This was dropped right at the primary ingress point. It was an admission requirement. Someone controlled the door. Someone vetted the clientele. This underground market moved here for a reason, and they packed up in a hurry."
Miller frowned, rubbing his chin. "You're overthinking it, Quinn. A bone? A broken compass? It's a bunch of drug addicts dressing up."
"Drug addicts do not possess this level of organization, nor do they leave behind hand-crafted brass tools crafted by artisans," Harlow countered. She walked back to Eva, stopping just inches from her. The height difference allowed Harlow to look down intimidatingly beneath the glare of the arc lights.
"You have a master's degree in Ancient History from Oxford, don't you, Ms. Kowalski?" Harlow asked.
Eva blinked, startled. "How do you know that?"
"I read the liaison file in the car," Harlow lied perfectly , having only just guessed the university based on the faded crest barely visible on the inside flap of Eva's satchel. "A woman with your credentials does not look at an organized, clandestine market and call it a teenage rave. You are lying to me."
"I am not," Eva said defensively. She pushed her round glasses up her nose, but she wouldn't meet Harlow's brown eyes.
"You know what this place is," Harlow pressed, her voice dropping to a dangerous, quiet register . "You know what they were selling. And you know what this compass is."
Harlow held the compass up. The needle was still dead-set on the bricked-up tunnel. "This compass tracks something. Energy. A signal. A portal. You arrived here before I did, and you spent your time circling the outer perimeter, not looking at the victim. You were trying to find out what the people selling their banned substances and enchanted junk left behind before my team could catalog it."
Eva stood frozen, her jaw clamped shut. Panic radiated off her small frame.
"My partner died three years ago," Harlow said, the grief morphing seamlessly into interrogator's steel . "He died in a scene that made no sense. Unexplained circumstances. Anomalies. Symbols carved into the brick that looked exactly like the ones on this platform. The department wrote it off. I am not writing this off."
Harlow pocketed the bagged bone token and then deposited the compass securely into her own coat pocket.
"Hey, that's evidence," Miller protested mildly.
"I'm taking point on the investigation," Harlow snapped, not looking at Miller . She kept her gaze pinned firmly on Eva. "I suspect you and your little clique are deeply involved in this, Ms. Kowalski. You are going to tell me exactly what this underground market really was, why it needs bone tokens, and where that needle points."
Eva squeezed her satchel. "You don't understand what you are dealing with, Detective."
Harlow's sharp jaw set into an unyielding line. "Then you had better start educating me. Because I am not leaving the dark until I find out what is hiding in it."