Trench-Smoke and Chisel

Boiling brine hissed against the copper seams of the diving bell, spitting yellow froth across Natsue's viewing port. The cracked convex glass distorted the dark into oily green smears. Beneath the grating floor, the twin pneumatic pistons of the dredge rig chugged with an irregular, asthmatic knock, wheezing steam into the cramped cabin.

"Gasket on the intake is blowing spit, chum," Chiyo shouted above the clatter. She shoved her shoulder against the iron bellows lever, grease dripping from her canvas sleeves down to her wrist wraps. "Two more notches of pressure and we'll be breathing roasted seal fat."

"Keep pumping," Natsue said. Her voice rasped behind her copper snout-filter. She reached down to tap the bronze dial bolted beside the ballast dogs. The needle quivered at forty-six atmospheres, buried deep in the red zone of Miyabi's floor. "Trench Seven opened a new throat an hour ago. If the crust cools before we hook the rim, the sulfur glazes into rock and Genki sells our skins to the furnace crews."

"Better than drowning in grease," Chiyo muttered, but her arms worked the iron bar in a steady, punishing rhythm.

Outside the thick glass, the sump was a vertical wall of black basalt dripping with chemical sludge. Miyabi did not have a sky, only the crushing belly of the sphere above, sweating cold moisture into the dark. Through the gloom, forty paces out, a chimney of basalt coughed boiling yellow plume into the water. Fresh, uncorrupted sulfur nodules crusted its jagged lip like pale gold teeth.

Natsue checked the copper fittings of her bone-handled pneumatic chisel. The compressed-air hose coiled at her hip like a sleeping serpent. She clamped her snout-filter tight, dogging down the wingnuts until the boiled leather bit into her cheekbones.

"I'm dropping onto the ledge," Natsue said. "Hold the winch line taut. If the tether slacks three spans, haul me back before the undertow feeds me to the flue."

"Don't lose the chisel," Chiyo said, wiping sweat from her eyebrows with a grime-caked thumb. "That valve cost two weeks of grain vouchers."

Natsue stepped into the airlock sump, flooded the chamber with scalding brine, and hauled the hatch open.

The pressure hit her like an iron hammer. The sealskin suit stiffened, seams groaning as forty-six atmospheres squeezed her ribs. She kicked through the murk, following the guide-line down to the jagged basalt shelf. Heat radiated off the stone in shimmering waves, curling around her boots.

The vent chimney towered before her, three fathoms tall, vomiting sulfurous steam into the abyss. Around its rim, fist-sized crystal nodules gleamed with clean, translucent amber. Not a trace of green phosphor rot. No chittering husks. Just pure, dry-burning brimstone worth its weight in silver vouchers at the High Citadel docks.

She unhooked an iron crate from her belt, set it against the rock, and brought the pneumatic chisel against the base of the nearest nodule. The chisel hissed, its hardened tooth hammering into the basalt with rhythmic cracks. Yellow shards sheared off, tumbling into her gloved palm. She packed them into the crate with hurried precision.

A shadow cut across the murky light.

Natsue did not look up with her head; she dropped her shoulder, rolling back against the chimney's basalt skirt. An iron gaff tore through the water where her neck had been a second before, striking sparks from the stone.

Two divers in blackened canvas armor stepped through the boiling steam. Their helmets were notched with the serrated crest of the Iron-Fin gang, hoses trailing behind them toward a heavy steam-skiff anchored above the shelf. The lead diver held a three-pronged boarding pike, its barbs freshly ground. The second diver swung a weighted cleaver meant for severing umbilical hoses.

"Guild claim, little minnow," the lead diver's voice rattled out through his brass diaphragm, tinny and wet. "Iron-Fin owns the throat. Drop the crate and swim, or we gut your bladders."

Natsue backed toward the chimney wall. Her boots scraped against the basalt. The second diver stepped to the left, angling to cut her safety line. If that air hose split under this depth, the pressure would force her lungs through the snout-filter before she could take half a stroke.

"Genki bought the dredging rights at fourth bell," Natsue shouted through her mask, keeping her voice flat. "Check the magistrate register."

"Register doesn't reach the sump," the lead diver said, leveling the pike at her throat. "Iron does."

He lunged.

Natsue did not retreat. Instead of parrying the thrust, she twisted her hips and drove the pneumatic chisel straight into the rusted brass exhaust petcock at the flank of the vent chimney. The chisel's piston hammered home, shattering the corroded valve stem with a shrill screech.

A jet of superheated, four-hundred-degree steam erupted from the fissure in a blinding white geyser.

The blast caught the lead diver across the chest. His viewing port cracked instantly under thermal shock, boiled water rushing into his faceplate. He dropped the pike, clawing at his throat as screams bubbled inside his brass snout. The second diver recoiled, blinded by the scalding cloud that boiled the surrounding brine into frothing foam.

Natsue pivoted off her left heel, swung the heavy butt of the pneumatic chisel into the second diver's knee joint, and kicked hard against the stone. The man buckled into the fissure, his hose tangling in the jagged slag.

She grabbed her iron crate, scooped the remaining amber nodules from the ledge until the box groaned with weight, and slapped the lid shut. Two paces away sat a second crate, dropped by the Iron-Fin crew when the steam erupted. She grabbed its handle with her free hand, kicking off the basalt shelf with both legs.

She yanked the signal cord thrice: haul fast.

The winch line snapped taut. The dredge rig above engaged its counterweights, the cable singing through the murky water as it dragged her upward away from the screaming steam vent.

Inside the diving bell, Chiyo threw herself against the hatch levers, hauling Natsue through the airlock before the pressure equalized. The water drained with a guttural slosh, leaving Natsue kneeling on the iron grating, panting hard as she tore the snout-filter from her face.

"You smell like roasted grease," Chiyo said, leaning against the boiler with a wild grin. Her teeth showed white against her coal-dusted cheeks. "Did you leave them anything?"

"Two broken teeth and an empty chimney," Natsue gasped, shoving the two crates across the grating.

Chiyo knelt, unlatching the lids. Yellow crystal caught the lantern light, clean and sharp, radiating dry heat without a drop of grease or vermin slime.

"Pure sulfur," Chiyo whispered, her grin widening. "Two full crates. That clears our rig debt for three months, Natsue. Genki can't touch the engine now."

"He'll try anyway," Natsue said. She wiped a smudge of black copper grease from her chin, reaching for her canteen of bitter tea. "He's a guildmaster. Eating his own workers is what keeps his fat warm."

"Still," Chiyo said, patting the iron lids, "we won the throat."

The dredge rig rattled as it cleared the trench rim, ascending toward the twilight shelf where the Under-Sump Guild anchored its floating shanties. But as the bell swung into the broader basin of Miyabi, the water turned a sickly, milk-pale hue.

Natsue leaned against the convex viewport, wiping condensation from the glass with her sleeve.

High above the trench basin, descending through the central transit shaft from the upper spheres, a warship cut through the gloom. It was not a guild skiff or a merchant tub. The hull was armored in sleek, black-lacquered iron, fitted with heavy drop-keels and outriggers designed for plunging through void shafts.

Dangling from its port and starboard booms were clusters of heavy iron cages, their bars stained dark.

Citadel execution skiff.

"Chiyo," Natsue said quietly, her voice dropping.

"What?" Chiyo asked, looking up from the crates.

"Cut the boiler fires," Natsue said, not taking her eyes off the glass. "Damp the exhaust flues. Now."

Through the murky water, the Citadel skiff drifted downward into the sump like a hunting spider, its prow searchlights carving cold white tunnels through the rising phosphor fog. On its iron gallows, the empty chains swayed with the deep-trench currents, waiting for flesh.