The fog rolled in off the Thames, thick and unyielding. It turned Shadwell's alleys into a world of half-heard footsteps and blurred gaslight. November 1867 had settled on London like damp rot, short days bleeding into longer nights, the air heavy with coal smoke and river mud that clung to wool and brick alike.

Thomas Fenwick sat in his third-floor office above the chandler's, the single gas lamp hissing. Its flame cast jagged shadows across peeling paper and the clutter of his trade: stacks of yellowed files, a chipped decanter half-full of cheap brandy, the cold remnant of a mutton pie, its grease congealed on the tin plate.

Fenwick leaned back, boots propped amid the mess, the chair creaking under his solid frame. He felt all of his forty-seven years in his joints, the ache of damp winters, old Yard brawls that had left scars on his knuckles, and a slight limp on the worst days. His face was hard: sharp cheekbones beneath salt-and-pepper stubble, a nose knocked around more than usual, and hazel eyes deep-set and watchful. He rubbed his temples, the ache building as the fog pressed against the narrow window.

Another night in the machine, he thought. The world's a powder keg, London's the fuse, and here I am, sifting ashes for shillings.

The office was proof of his fall. Over a year since he'd walked out of Scotland Yard, disgust at the Hyde Park truncheons cracking skulls in '66, the bribes that flowed uphill from the swells who feared the working man's voice, the brass who looked away when it suited them. They'd called it resignation. He'd called it waking up. Now he took the leavings: stolen trinkets from Mayfair drawing rooms, straying husbands reeking of gin, bodies the peelers couldn't be bothered to chase beyond a cursory glance. The latest, a necklace pinched by a footman with a grudge and an opium habit, had closed that afternoon. An easy confession after Fenwick cornered him in a Limehouse back room, a quiet shove against the wall, and words that landed heavier than fists. It paid the rent on this perch, nothing more. No glory, no headlines. Just the satisfaction of a puzzle slotted together, even if the pieces were small and tarnished.

He grabbed the decanter, poured brandy into an old glass, and took a drink. It was a brief fire against the chill seeping through thin panes. He swirled the liquid, watching it cling to the sides. Outside, drizzle tapped the glass, smearing the view of the alley below into greys and blacks. Gas lamps haloed in mist, casting long shadows from huddled figures hurrying home. The clock showed half past nine. Soon, doors would be bolted against the cold and the city's underbelly would wake.

Headlines from The Times drifted back through his mind: the National Society for Women's Suffrage formed a week and a half before; the Ferndale Colliery explosion up north just a week gone, burying near two hundred men; whispers growing louder after the Manchester rescue gone bloody, with three Irish lads now doomed to hang at Salford Gaol; riots already brewing in the Irish quarters of Whitechapel and Stepney.

A sharp knock shattered the quiet, pulling him back. Fenwick set the glass down carefully, his hand hovering over the Beaumont-Adams revolver on the desk. The cold metal was a reassurance in a world where talk often turned to teeth. "Enter," he called, voice low and gravelly.

The door opened on a skinny shadow that slipped inside, bringing a gust of damp that made the lamp flicker. Jeremiah Doyle, Jemmy, Ginger Jemmy on the streets, was eleven or twelve, wet orange hair plastered under a battered cap, freckles lost under grime smeared like war paint. His oversized jacket dripped onto the boards, trousers patched at the knees and cuffed high to hide the holes, boots leaking Thames muck with every squelching step. Sharp eyes darted around the room, taking in the pie remnants and the decanter before settling on Fenwick.

"Blimey, Mr. Fenwick," the boy said, his Cockney accent thick with an Irish burr. "It's comin' down like the angels forgot the plug. Proper rotten night, innit? Me boots is soakin' through, and the fog's thick as pea soup gone bad."

Fenwick studied him, suppressing a wry twitch at the corner of his mouth. Jemmy was one of his better irregulars, ears everywhere, a nose for trouble that kept him one step ahead of the peelers or the workhouse beadles. The lad's da, Patrick Doyle, had been a docker who'd vanished years earlier, swallowed by the river in an accident, dragged off to debtors' prison, or lost to cholera like so many; the stories varied with the teller. Jemmy survived on his wits, scavenging and informing, loyal to Fenwick because the detective paid in silver and treated him like a source rather than a pest to be shooed.

The gap in Jemmy's grin brought his Clara back. She'd once shown him a lost tooth, small and waxy in her palm, absurdly proud, and he'd called her a tough little thing. He hadn't known it was one of the last things he'd call her. Nothing useful in that direction, Thomas. Fenwick looked back to Jemmy.

"Sit if you must, lad, but mind the drip," Fenwick said, gesturing to the rickety stool by the desk. "What brings you up three flights in this weather? Not another tale of pinched loaves from the baker's cart, I hope. Last time it was a false alarm. Turned out to be rats with ambition."

Jemmy perched on the stool, shaking his head with a grin. "Nah, guv, nothin' so tame. Somethin' queer down Wapping Stairs. Mudflats at low tide. Bloke turned up floatin', throat cut proper, ear to ear like a smile gone wrong, and a mark on 'im. Not a tattoo like the sailors get from the Indies. Somethin' carved fresh, still oozin' when Timmy the mudlark poked 'im. Serpent bitin' its own tail, coiled like it's eatin' itself forever. Peelers crawlin' all over, but they ain't sayin' much, just mutterin' about dock fights and Fenians maybe. Thought you'd want the word, seein' as you chase the odd ones what the bluebottles ignore."

Fenwick's interest sharpened, the old hunt stirring in his veins like the brandy had. Marked men again. Whispers had reached him weeks back, tavern talk in the dockside pubs of a group dabbling in sparks and wires, branding their own for some galvanic rite, promising power or resurrection or whatever madness filled the void left by cholera graves and empty bellies. The Yard would chalk it up to a brawl over wages or women. He knew better. This is the third marked body in a month.

He leaned forward, elbows on the desk, eyes locking on Jemmy's. "Slow down, nipper. Who found him exactly? Timmy, scrawny lad with the limp? What time? And the mark, describe it proper. Size of a hand? Clean cuts or ragged?"

Jemmy fidgeted under his gaze but straightened, eager to impress. "Aye, Timmy with the bad leg, pokin' for coppers and bits in the silt 'round eight, when the tide was out full. Bloke weren't no docker neither, good wool coat, not patched like mine, and a watch chain still danglin', silver by the look. Pockets not rifled, which is odd 'cause the mudlarks'd strip a corpse quick as a blink. Mark was on 'is chest, right over the heart, 'bout the size of me palm. Burned in, like a brand, but neat, proper neat. Serpent all twisty, head swallowin' the tail, edges crusted black with blood and mud. Gave Timmy the shivers; he scarpered quick after callin' the peelers. I snuck a peek meself before they shooed us off. Smelled funny too, not just river stink, but summat sharp, like burnt wire."

Fenwick nodded slowly, mind turning the details like tumblers in a lock. Burnt wire, the tang of electricity. He'd heard talk of Society lectures on galvanism. Men fiddling with coils and batteries in back rooms off the Strand, flirting with life and death like it was a parlour game. And the snake, old symbol, but carved on a corpse? A warning, or a claim. Another missing docker last month… whispers of 'experiments' in the warehouses. And now this? Patterns in the chaos.

"Funny smell, eh? You've got a nose like a bloodhound, lad. Anyone lurking about before the peelers arrived? Shadows that didn't move right, or a face you half-knew?"

Jemmy shrugged, but his eyes flicked to the window as if the fog might listen. "Nothin' sure, guv. But the mist was thick, and Timmy swore he heard footsteps splashin' away up the embankment. Coulda been a watcher, or just the river playin' tricks. Me da used to say the Thames keeps secrets, but sometimes it whispers 'em back wrong."

Fenwick gave a dry chuckle. "Your da had it right, river's a liar, same as most men. Good work, though. Better than half the constables I trained." He fished a sixpence from his waistcoat pocket, tossing it across the desk. The coin glinted in the lamplight before Jemmy snatched it mid-air.

"Ta, Mr. Fenwick! That's a proper bit, enough for hot eels and a mug o' small beer. I'll keep me ears pricked. You reckon it's summat big? Like them Fenian bombs they whisper about?"

Fenwick's expression hardened slightly. "Big enough to swallow lads like you if you're not careful. So head down and scarper now, before the night turns uglier."

Jemmy hopped off the stool, tipping his cap with a grin. "Right you are, guv. Blimey O'Reilly, it's freezin'. Best be off." He darted out, the door banging shut behind him, leaving a puddle and the scent of river mud in his wake.