A workshop floor covered in stone grit was an insult to the trade.
Austin stood by the shattered eastern wall of Subterranean Floor 1, hands propped on his hips, coughing against a sour fog of diesel fumes and quartz dust.
Inside the breach sat the twenty-foot snail-skiff, its hybrid combustion engine still chugging with an off-time, rattling idle: *chug-chug-clank, chug-chug-clank.* Every few strokes, the exhaust stack puffed another ring of greasy soot into the vaulted cavern. Ten feet to his left, inside the sealed two-inch basalt recycling bin, thirty-one muffled voices were hammering on the underside of the floor hatch with spear butts:
*THUMP-THUMP-THUMP!*
"RELEASE US!" Tie Feng's voice was muffled by two inches of vitrified rock. "WE ARE THE IMPERIAL IRON PAVILION! BY DECREE OF EMPEROR YAN LONG, YOU ARE COMMITTING GRAND TREASON AGAINST THE CROWN! OPEN THIS HATCH OR TASTE THE WRATH OF THE NINE PROVINCES!"
Austin picked up his five-foot Stellar-Steel pipe wrench and tapped the iron inspection grate once.
*CLANG.*
The tool had zero internal damping. The strike released a piercing, high-frequency harmonic ping that rang through the enclosed stone pit like a six-hundred-pound bronze temple gong. Down in the darkness, thirty-one men screamed, dropped their weapons, and clapped both hands over their bleeding ears.
"Quiet in the compost bin," Austin said through the bars, voice deadpan. "I haven't piped in the greywater wash cycle yet. Keep pounding on that lid, and I'll route the high-pressure waterwheel line straight through the grate and hose you down."
The noise stopped instantly. Only ragged breathing and frantic whispering drifted up:
*"Quiet! The demon said he’d flood the chamber..."* *"Director, don't move. He has an ancient artifact..."*
Austin turned back to his conveyor line with a weary scowl.
He pulled a dry cotton rag from his apron and ran a thumb along the top guide rail. When he pulled it away, his skin was coated in a black, sticky paste of diesel soot and crushed quartz.
"Severe particulate contamination," Austin muttered, rubbing the grit between two fingers. It felt like eighty-grit sandpaper. "Look at this mess. You let abrasive silica into bronze sleeve bearings, and it embeds into the soft metal. It turns the bearing into a lap. In ten operating hours, it'll score the spirit-iron shaft by thirty thousandths. I need an industrial cyclone dust collector, and I need it yesterday."
A familiar golden chime chimed deep behind his eyes:
*HIIIIIIIIIIISSSSSSSSSSSSSSSS.*
Deep beneath the vitrified basalt floor, where the diverted underground stream passed through the drainage sump, Austin's internal core temperature spiked from fifty thousand Kelvin straight to seventy-five thousand Kelvin.
The heat hit the four-hundred-and-fifty-liter-per-second water flow like a falling star.
Water didn't boil. It blew straight past the critical threshold—three hundred and seventy-four degrees Celsius and twenty-two megapascals—in less than a heartbeat. It flashed into supercritical steam: a dense, invisible fluid with the mass of boiling brine and the explosive expansion velocity of detonating artillery powder.
The floor tiles began to scream.
A high-pitch whine shook the cavern. Razor-thin jets of dry white vapor whistled through the expansion joints between the floor stones.
Beside the workbench, Pug’s three heads shot up. The Three-Headed Nether-Solar Cerberus backed away from the floor seams, sniffing the boiling vapor, his claws clicking nervously on the obsidian.
Austin glanced at the flashing red warning readout: `Chamber Pressure: 45.2 MPa`.
"Holy hell," Austin muttered, safety goggles slipping down his nose. "Forty-five megapascals. That’s four hundred and fifty atmospheres. Section One of the ASME Boiler Code explicitly states: you never, ever let boiler pressure exceed fifteen megapascals without a primary relief valve! If I don't vent twelve thousand cubic meters of supercritical vapor right now, this whole mountain is going to blow its top like an overcharged pressure cooker!"
He scanned the hall for an opening.
His eyes locked onto the rear housing of the twenty-foot snail-skiff wedged into the wall.
Behind the machine stretched the borehole it had just cut: four feet in diameter, forty meters long, angled thirty degrees upward through solid rock, venting straight out into the river valley where the Iron Pavilion's camp sat.
A dead-straight, unobstructed exhaust flue.
Austin grinned. A wide, tired, tradesman grin.
"Look at that draft geometry," Austin muttered. "A pre-drilled, forty-meter directional pressure flue pointed straight away from my shop. It’s like the game engine felt the pressure spike and spawned me an emergency stack."
He grabbed his High-Frequency Thermal Plasma Pickaxe.
Moving with frantic speed, Austin sliced a curved trench through the vitrified floor from the boiling sump pit straight into the rear exhaust cowling of the borehole.
In thirty seconds flat, he slammed a circular flapper valve forged from solid Stellar-Steel over the conduit opening. He hung the plate on two heavy bronze barrel hinges and pinned it to a counterbalanced four-foot iron lever.
Austin immediately ran his pre-flight safety checks. A relief valve that sticks closed on an overpressured vessel is just a bomb with a delay timer.
He tapped the bronze hinge pin with the tip of his brass drift punch: zero binding. He lifted the four-foot lever two inches by hand, checking the seat clearance. The ground face of the Stellar-Steel disc broke away from the beveled rock flange with a clean, unblemished hiss, seating back down true under the deadweight of the counter-bob.
Pug trotted over on heavy padded paws, his left head sniffing the hot bronze hinge while his middle head examined the counterweight. The hound let out a soft sneeze at the tiny puff of vapor, but his three tails wagged with approval. The dog planted his front paws firmly, giving Austin an affirmative grunt.
"Inspection passed," Austin nodded. "Stand clear, Pug. Hearing protection on."
Austin dug his straw sandals into the vibrating stone floor. He gripped the four-foot lever with both hands, took a deep breath, and yanked it down with his full weight!
*CLACK-FWOOOOOOOOOOOOOOOOOOOSH!*
***
Up on the surface, the eastern river valley was peaceful.
The remaining one hundred and seventy battle-miners of the Iron Pavilion were enjoying a slow mid-morning. Lounging around their twenty iron-plated siege wagons, they were boiling iron cauldrons of salt mutton over driftwood fires, passing around jugs of sorghum moonshine, and joking about how long it would take Director Tie Feng to strip the monks bare.
"Director probably has them scrubbing his boots by now," an enforcer squad leader laughed, picking a sliver of mutton from his teeth with a rusted bodkin. "Another hour, and we'll be loading thirty tons of dragon iron onto these wagons."
Beneath their boots, the river gravel began to whistle.
*EEEEEEEEEEEEEEEEEEEEEE!*
It was a sharp, rising scream—the sound of an over-torqued steam turbine spinning until the rotor blades shear off. The noise tore straight out of the dark mouth of the central drill hole.
"What's that whistling?!" the squad leader yelled, dropping his bodkin into the gravel. "Did the skiff hit an underground gas pocket?!"
The borehole answered with a blast.
*BOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOM!*
A three-hundred-foot plume of pure, blinding white supercritical steam erupted from the tunnel mouth at eight hundred miles an hour!
The shockwave broke the sound barrier with a concussive boom that flattened the river reeds and blew every campfire into charcoal dust.
The steam jet was four hundred degrees of scalding, supersonic fury. It shot skyward like a white pillar holding up the clouds, roaring like fifty freight trains crossing a wooden trestle. The thermal blast tore through the Iron Pavilion’s staging camp in three seconds flat!
*CRASH! SMASH! WHOOSH!*
Twenty four-ton siege wagons were lifted off the gravel like cardboard boxes. They cartwheeled through the air, smashing into the granite hillside in showers of splintered oak and bent iron axles.
Canvas tents vanished into burning rags. Iron stew cauldrons skipped across the river shallows like flat pebbles. The two-headed Earth-Monitor lizards let out shrill, terrified squeals, snapping their three-inch mooring chains like twine and stampeding down the valley at full gallop, trampling their own supply crates to dust.
One hundred and seventy battle-miners were knocked off their feet by the blistering gale.
They tumbled across the stones like dry pinecones in a gale, their black-iron armor heating up until wool tunics began to smoke! Shrieking in blind, unvarnished panic, the miners scrambled to their feet, dropped their pneumatic pikes, and ran east as fast as their legs could carry them:
"THE DRAGON! THE MOUNTAIN DRAGON HAS EXHALED!" "AN EARTH-FIRE VOLCANO! THE ROOTS OF HEAVEN HAVE CRACKED! RUN!"
Within two minutes, the entire expeditionary camp had evaporated. Only steam, scorched dirt, and scattered mutton bones remained in the valley.
***
Fifty meters underground, on Subterranean Floor 1.
The deafening roar through the diversion pipe tapered off into a steady, rhythmic sigh. On Austin's developer display, the chamber pressure needle dropped from forty-five megapascals down to a calm, manageable two point one megapascals.
The violent, supersonic draft created by the steam siphon had acted like a giant chimney flue.
Under basic Bernoulli principles, the high-velocity steam jet roaring down the forty-meter tube created a massive low-pressure induction zone behind it. The resulting Venturi effect turned the borehole into a colossal forced-draft exhaust fan. Every lingering speck of diesel soot, every grain of floating quartz dust, and all the noxious exhaust that had fouled the cavern was sucked into the draft pipe and blasted straight out of the mountain.
The air in Floor 1 was now ice-cold, smelling of river stones and clean ozone.
Austin stood by the relief lever, his hemp apron spotless.
He pushed his brass goggles up into his hair, took a long, deep pull of the crisp air, and exhaled with profound contractor satisfaction.
"Air quality index: one hundred percent," Austin said, wiping a clean rag across the conveyor frame. "Zero particulate. Proper draft velocity. You respect ASME boiler standards and verify your valve seats, and the plant takes care of you."
He walked over to the Slag Recycling Bin. Pug trotted alongside him, tail wagging with a steady *thwap, thwap* against Austin's shin.
Inside the dark pit, thirty-one miners were huddled together in dead, petrified silence, shaking so hard their loose armor plates jingled like tin cups.
Austin tapped the iron grate once with the tip of his Stellar-Steel wrench:
*Ting.*
"Hear that? Clean draft," Austin said down through the bars. "Optimal workshop atmosphere restored. No need to thank me. Just don't track any more mud in here."