A Snapped Line

A sweep who runs across wet slate in the dark usually dies with grease on his heels and a broken neck in the gutter. Out on the pitched roof, an Ash-Weaver had eight hooked tarsi, thirty feet of silk, and the advantage of open ground. Inside the shaft, it had only the width of the brickwork.

"Baffle plate," I barked, grabbing the iron slab resting against the chimney rim. "Help me slide it over the throat. Now!"

Lázaro choked back a spasm of wet coughing, dropped to his knees, and threw his weight against the rusted handle. The iron dragged across the chimney coping with a screech that set my back teeth on edge.

Below us, the chittering doubled in pitch. Iron claws raked against flue tile—clack-clack-clack—ascending at the speed of a sprinting hound. A blast of oily coal-gas puffing through the gap between the plate and masonry nearly turned my stomach. The beast was using the rising thermal draft like an elevator, riding the updraft of tenement cooking fires.

"We are shutting off its air," Lázaro wheezed, his knuckles white against the flange. "Master, it will burst right through the slate!"

"We are shutting off our draft, not its air," I corrected, slamming my boot heel down on the plate's locking pin. "We leave a three-inch throat. Enough to draw the smoke away from our noses, but narrow enough that the brute has to drag its carapace through single file."

The heavy damper seated with a hollow thud. The vibrations through the slate beneath our knees changed instantly. The rhythmic scraping slowed, baffled by the sudden drop in ventilation, but the heat radiating through the lead flashing spiked ten degrees in seconds.

I unbuckled the twin copper cylinders from Lázaro's shoulders and hauled the heavy rig onto my own back, settling the straps over my scarred leather coat. A boy with soot-lung couldn't maneuver a forty-pound compressor down a twenty-inch chute, and the sweep covering the rear needed the weapon. I uncoiled thirty feet of tarred hemp line from my hip spool. "Harness clips to the flue rim anchor. Primary karabiner on my belt, secondary on yours. You go down first to the inspection collar, then drop your feet on the iron rung while I back you with the brine nozzle."

Lázaro's throat clicked as he swallowed. He peered over the lip of the dark square hole. "We're going in? Down toward the teeth?"

"Landlord Trilla charges six copper groats a week for these garret rooms," I said, wrenching his brass ring tight against his chest harness. "He advertises warmth and ventilation. It would be bad for business if his tenants' hearths became an open spit for subterranean vermin. Besides, you don't earn your bread on the ridge tiles. Sweeps live in the flue, boy."

I clipped my brass swivel into the lead eyelet hammered into the outer stack.

Lázaro did not argue. He bit down on his lower lip, swung his short legs over the soot-blackened lip of the chimney, and slid into the vertical well. The shaft was twenty inches square, lined with crumbling yellow brick and thick layers of tarry soot that flaked off under his heels like burnt pastry.

"Feet wide," I told him, dropping my boots in behind his shoulders. "Chimney-jam. Back against the north face, knees braced against the south. If you slide, dig your brass toe-caps into the mortar joints. Never rely entirely on the rope."

The darkness swallowed us three feet below the rim. Above us, the slate roof and the greasy yellow glow of Cadernera's gas-canopy vanished, replaced by the suffocating gloom of the exhaust main.

The smell here was rancid. It was not ordinary chimney sweepings—not the dry, mineral bite of Welsh coal or the sweet grease of kitchen lard. It was the thick, sulfurous reek of concentrated coal-gas mixed with rotten bone and curdled pitch.

Every four feet, iron climbing rungs were driven into the corners of the flue. They were old, crusted with vitrified soot that felt like broken glass under my leather palms. My fingers moved by instinct, probing every seam. A blind sweep learns to read masonry with his skin; bad mortar feels spongy, while cracked brick gives off a distinct thermal tick when the heat flexes the clay.

Two yards down, my right palm hit cold iron where there should have been only lime-mortar.

I halted, locking my knees against the bricks. "Hold position, Lázaro."

"Holding," the boy gasped from five feet below me. His boots scraped against a protruding header. "Master, the heat... it is coming from the side wall, not just the bottom."

I ran my fingers along the smooth, cool curvature embedded in the masonry. It was a cast-iron sleeve, six inches in diameter, mortared directly into the tenement's flue wall.

No tenement builder installed cast iron inside a secondary chimney stack. Cast iron was heavy, ruinously expensive, and reserved for municipal high-pressure mains. More than that, the seam had been wrapped in oiled lead tape and bolted with hexagonal head-screws.

I felt along the casing until my thumb found an inspection seal stamped into the flange. Three raised ridges crossed by an iron hammer: the municipal foundry crest of Baron Morillo's Ward Dampening Authority.

"Master? What is that?" Lázaro asked, his voice echoing thin and tight in the shaft.

"An intake bypass," I murmured, testing the brass petcock fitted to the sleeve. "Someone cut open the boardinghouse chimney and tapped a pressurized gas lead straight into the draft column."

A cold prickle ran across the nape of my neck beneath the grime. Ash-Weavers didn't burrow into buildings by accident. They chased pressure and heat. If someone ran a pressurized coal-gas feeder directly into a tenement flue, they were not just neglecting municipal maintenance. They were laying a feast. They were luring the brood upward into the bedrooms.

"Why would the Baron put gas in a chimney?" Lázaro whispered.

"He wouldn't," I said flatly. "Unless he wanted the building to burn without having to explain where the spark came from."

Below us, deep in the throat of the house, a sudden draft roared.

The air pressure inside the shaft reversed with the violence of an opening sluice gate. A gust of superheated gas blasted upward, tearing past our legs. My lungs seized on instinct, coughing violently against the choking haze.

Then came the sound.

It was no longer climbing four floors down. It was right beneath the second-story floor joists, clawing through the narrow bends of the brickwork with savage fury. We could hear the rhythmic snapping of its mandibles, like shears clipping through wet leather.

"Mateiro!" Lázaro screamed.

A jet of boiling, iridescent pitch splashed against the bricks three feet below Lázaro's boots, hissing as it bubbled against the soot. The light from the chemical glow illuminated the shaft for a split second: eight segmented legs covered in needle-like bristles, hauling a bloated, ash-gray abdomen up the vertical chute.

"Brace!" I bellowed, reaching down to unholster the brass brine lance clipped to my pack. "Kick your heels into the brick, boy! Don't let your line go slack!"

Lázaro kicked out frantically, trying to find purchase against the crumbling mortar. His left boot struck an old iron mounting bracket—a rusted anchor left behind from an earlier chimney liner.

The metal had been baked brittle by the coal-gas feeder. Under the sudden shock of his weight, the bracket sheared with a sound like a pistol shot.

The jagged stub of broken iron whipped across his safety tether.

The hemp cord, dry and rotted by decades of sulfur fumes, parted instantly.

Lázaro didn't even have time to shriek a full word. His small body peeled away from the wall as gravity took him, his fingers clawing uselessly against the slick soot.

"Master—!"

The cry plummeted into the dark.

I didn't think about the pressure gauge on my brine tank. I didn't think about the monster climbing the shaft with its mandibles open to catch whatever meat tumbled down from above.

I unlocked my knees, kicked my boots free of the masonry wedges, and released the safety catch on my harness.

I dropped straight down into the black furnace after him.