The Teeth of the Siphon

The roar of the Lower Siphon hit us twenty feet below the rim, smelling of wet iron, tallow, and cold mineral spray.

The central hoist was an open iron cradle suspended from four braided copper cables. Every six seconds, the cage shuddered as the teeth of the guide rails engaged the perimeter gears of the shaft. My left hand gripped the safety stanchion so hard the knuckles ached, but the tremor crept up my wrist anyway, a dull vibration that had nothing to do with the machinery and everything to do with the blood I had washed from my mouth at sunrise.

Vance stood two paces to my right. His weight was balanced over the balls of his boots, completely unaffected by the violent sway of the platform. His left hand rested flat against his trench shield, his thumb running a steady circle over the notched bronze rim.

"Three minutes to the staging floor," he said. The words barely carried over the grinding bronze below. "The sluice run lies past the second rocker arm."

"I know where the sluice run is," I replied, keeping my eyes fixed on the descending darkness. The air down here was thick with atomized water that clung to my eyelashes and cooled the lingering heat of my migraine. "Corin will take the high catwalk to reach the flood valves. He carries a weighted cipher case strapped across his ribs."

Vance turned his head slightly. His gray eyes flicked from my face to the iron struts passing overhead. "You talk about this boy like you took supper with him."

"He killed me once," I said under my breath.

"What was that, Fletcher?"

"I said he is thorough. If he spots us before we clear the gantry, he has the elevation and three racks of iron throwing darts."

Vance adjusted the leather strap of his trench blade. "Elevation is an advantage until the footing moves. In the Siphon, everything moves."

The cradle dropped through a dense cloud of vented steam. Below us, the true scale of the Barrow-Mark's kinetic engine opened into a cavernous vault carved out of black schist. Massive bronze gears, some thirty paces across, turned in interlocking tiers along the wet stone walls. Counterweight cradles the size of timber wagons rose and fell on counterbalanced chains, their rhythmic thud sending tremors through the bedrock.

A sharp jolt racked the cage as the governor brake engaged, bringing the platform to a groaning halt level with the lower maintenance gantry.

I stepped toward the gate before the latch had settled.

Vance caught my elbow, his grip a solid band of pressure through my damp wool sleeve. "Hold your line."

"The sluice valve index operates on a twelve-minute drain cycle," I said, looking back at him. "Every minute we stand on this grate is a minute closer to the culverts opening beneath the trade convoy."

"And if you trip an unmapped tension wire, neither of us reaches the valve," he said smoothly. He released my arm, though his fingers lingered for a fraction of a second against the rough fabric before dropping back to his hilt. "That makes the fourth time today you have tried to leap into an open gear-hub. My contract fee just doubled."

"You already took half the grain concession, Captain."

"The grain feeds my men," Vance replied, his jaw tightening as he stepped past me to unhook the gate. "The surcharge feeds my patience."

I stepped out onto the rusted iron grating behind him.

The walkway was narrow, scarcely wide enough for two men to pass abreast, suspended over a churning race of black water fifty feet below. The spray coated the metal in a greasy film of pulverized shale and machine oil. Every joint of my body protested the cold, the muscle cramp in my right shoulder throbbing with each breath. Loop or no loop, my flesh remembered the weight of the stone slabs and the bite of Corin's garrote.

We moved in silence beneath the turning teeth of the third-tier reduction gear. The noise here was a physical weight, vibrating through the soles of our boots and rattling the teeth in our skulls. Vance moved like an iron bolt through oil, silent and deliberate, his shield held low to cover his vitals while his eyes swept the overhead catwalks.

I kept three paces behind him, counting under my breath.

One. Two. Three. Four.

The escapement wheel above our heads clicked through its four-stroke cycle. A puff of warm sulfur exhaust vented from a brass cylinder to our left, whistling through the copper grates.

"He is not at the valve station," Vance said quietly, stopping at the edge of an arched stone bulkhead.

Before us lay the central manifold: an iron junction where three massive sluice conduits converged into a single subterranean drain. Above the manifold, a web of narrow maintenance walkways crisscrossed the cavern ceiling like a spider's loom. The valve wheel itself was an enormous spoked iron helm, locked in place by a spring-loaded bronze detent.

The area was empty. The grease pots were undisturbed.

"He knows we are here," I said, scanning the shadows between the overhead structural ribs. My head throbbed in sharp pulses. "The hoist made too much noise on the descent."

"Then he is waiting for a clear lane," Vance murmured.

The air shifted.

A faint scrape of metal on stone cut through the rhythmic thrum of the gears.

Three things happened at once.

The torch overhead went dark.

A crossbow bolt hummed through the mist.

Vance stepped directly into my space.

His trench shield came up with a deafening clang as the steel quarrel struck the center boss, the force of the impact spraying sparks across his chest. The smell of scorched iron flared between us. His back pressed against my shoulder, solid and unyielding, shoving me back into the recess of the stone archway.

"Gantry four," Vance said, his voice flat and perfectly controlled. "Crossbow and light plate."

"He has three more shots in that magazine," I warned, pressing my spine against the damp rock to steady my trembling hands. "Then he switches to the short blade."

A second bolt struck the flagstones at our feet, shattering against the granite and sending sharp iron shards skittering across the walkway.

From thirty feet above, a voice called down, warped by a brass respirator mask. "Ironwright! The Chief Engineer gave you clear orders to secure the High Harrow! What are you doing in the lower hubs with guild baggage?"

Vance did not answer. He kept his shield angled upward, his trench blade drawn and resting along the notched rim.

"Penhaligon bought your sword, mercenary!" Corin shouted from the shadows of the upper gantry. The mechanical hum of his magazine reloading echoed off the cavern vault. "He did not buy your insubordination. Step aside and let me drown the carts, or you swing from the same gibbet as the convoy!"

"My contract is for territorial defense," Vance said, his voice easily carrying over the water. "Flooding a sovereign trade spur without a sealed court writ is breach of terms."

"The writ is sealed!"

"Show me the copper cylinder," Vance replied, taking a slow, measured step forward to draw the courier's line of sight away from my alcove. "Step down to the manifold and show me the seal, boy. Or are you too small to carry an honest signature?"

Corin laughed, a dry, metallic rattle behind his respirator. "You talk too much for a dead company."

A third bolt buried itself into the heavy timber bumper of the walkway, inches from Vance's boot.

I did not wait for the fourth.