The white plume erupted from the rim of the floor hatch, scalding the varnish off the ceiling beams in dry, curling sheets. Sybilla ran the updated figures through her mind before the iron hatch had even clanged against its backstop. The primary exhaust was venting eight hundred cubic feet of volcanic vapor per second. Her epidermis would suffer full-thickness destruction within four point two seconds. Tracheal necrosis would follow at six. Even if her fingers locked around the cast-iron wheel before the flesh sloughed off the bone, her body weight of one hundred and twenty pounds lacked the torque required to overcome forty bars of backdraft. Her probability of closing the valve before somatic cessation was zero point zero zero three percent. Levin, however, stood thirty feet away, currently eating a ginger biscuit behind a reinforced blast partition. If the basement detonated, Levin’s survivability was zero. Therefore, her personal loss of function was an acceptable operational expense. "Levin," Sybilla stated over the shrieking pipes, keeping her tone flat enough to level a carpenter’s shelf. "Finish your snack, then proceed north to Vault Twelve. Do not deviate for stray cats." She put her boot onto the top rung of the descent ladder. A heavy brass shoulder struck her squarely in the ribs. The impact pitched Sybilla across the stone floor. She rolled, coming to rest against a rack of pneumatic drills, her spanner clattering against the flagging. "Are you out of your lunatic mind?" Corso roared, his voice cracking against the scream of the ruptured flue. He stood above the open pit, his trench coat already smoldering at the hem. His left arm—the heavy, reinforced piston assembly she had forced him to calibrate three nights ago—glowed dull bronze in the vapor. His right side leaned heavily on his crutch, but his face had lost every shred of the trembling drunk who had whimpered about his missing whiskey bottles. "Get away from the perimeter, Corso," Sybilla said evenly, rising to her knees. "Your spatial interference has cost us one point eight seconds. Your biological tissue will incinerate just as quickly as mine, which constitutes a redundant loss of capital." "Shut up! Just—for once in your miserable, ledger-keeping life, shut your mouth!" Corso hurled his crutch to the floor. "Your skin is meat, Sybilla! You're entirely meat!" He slammed his left fist against his chest plate with an echoing clang. "Tungsten-carbide casing!" he shouted, spittle flying from his lips into the haze. "Ceramic thermal insulation rated for three thousand degrees! You built this monstrosity, remember? You threatened to break my fingers if I didn't mill the joints to three microns! That makes me the statistically superior idiot for this job!" "The pneumatic seals in your shoulder joint have an operating ceiling of four hundred and fifty degrees," Sybilla countered, lunging toward him. "The thermal expansion will fuse the sleeve bearings!" "Then I'll break the damn gears with my good hand!" Corso didn't wait. He dropped through the hatch like an anvil falling into a boiling kettle. The cloud swallowed him whole. Down in the darkness of the sump, iron screeched against iron. A wet, tearing roar blasted upward through the opening as the main vent shuddered, spitting flecks of molten flux. Sybilla reached the edge of the pit. The searing draft scorched her eyebrows and dry-roasted the skin of her cheekbones, but she did not blink. She watched the glowing red silhouette down in the black water. Corso was knee-deep in boiling runoff. His wool trousers were charring to gray ash. His natural right arm was wrapped around an overhead pipe to keep him upright, welted instantly against the pipe's scalded flank. A sound ripped from his throat—raw, animal, stripped of all despair and soaked in pure, stubborn rage. His mechanical arm clamped onto the valve. "Turn it, Corso!" Sybilla shouted down the shaft, her voice sharp as an executioner's bell. "Clockwise! Forty-five foot-pounds! Do not compensate for the backlash!" "I'm... turning... the damn... thing!" he shrieked. The metal groaned. Internal hydraulic fluids in his prosthetic began to boil, whistling through the relief gaskets like tea kettles. The ceramic plating on his forearm crackled, cobwebbing under the sudden thermal spike. The skin of his bare cheek was bubbling, peeling back in red welts, but his jaw clamped down until blood ran from his gumline. He threw his whole frame against the lever. His synthetic elbow hissed, grinding metal shavings into the steam. *Clack.* The bevel gear engaged. *Clack-clack-screeech.* With a concussive thump that rattled the floor plates beneath Sybilla's knees, the primary safety slug slammed into its socket. The bellowing jet collapsed inward. The white plume died instantly, choked down to a pathetic trickle of gray fog that drifted sluggishly through the sump grating. The basement went eerily, violently quiet. Down in the murk, Corso let go of the pipe. He folded sideways into three inches of hot, stagnant water with a dull, wet splash. Sybilla dropped through the hatch without hesitation. She landed in the pool, ignored the scalding heat soaking through her leather boots, and hauled Corso up by his collar. The ruined wool of his shirt came away in sticky strands against his burned shoulders. His mechanical arm was dead weight, locked rigid at a ninety-degree angle, its brass housing scorched pitch-black. She dragged him up the ladder with deliberate, rhythmic exertion, her breath coming in ragged gasps through soot-blackened nostrils. When she dumped him onto the upper floorboards, he slumped against her chest, shivering violently despite the radiant heat of his skin. "Status report," she demanded, checking his radial pulse. It was thumping at one hundred and forty beats per minute. Irregular, but present. "I... broke... your valve," he wheezed, his cracked lips peeling back in a dazed, agony-riddled grin. "Deduct it... from my allowance..." "I will," Sybilla said. Her hand lingered for half a second on the unburned skin at the side of his neck, confirming the arterial rhythm. "You performed at ninety-four percent efficiency. An adequate return on investment." Corso groaned, leaning his forehead against her collarbone as his vision flickered out. A dry metallic click broke the silence from across the room. Sybilla did not turn her head quickly. She merely shifted Corso’s deadweight an inch to the left to ensure his vital organs remained behind her armored corset. Uncle Yvan stood near the rack of brass gauges, holding a serrated trench knife in his left hand and a miniature six-shot pepperbox pistol in his right. He had shredded Levin's titanium wire net using an acid vial from his signet ring, though the flesh on his palms was crisscrossed with deep, bloody lacerations. His eyes were wild, bloodshot, stripped of every ounce of aristocratic polish. "You impossible, cold-blooded little bitch," Yvan rasped, cocking the hammer of the pistol. He leveled the barrel directly at Corso’s exposed temple. "Do you know what those geothermal tracts are worth? Do you know the fortunes the Consortium promised me? You were supposed to rot in this sewer with this cripple! You were supposed to blow up!" "Your financial modeling was inherently flawed," Sybilla remarked, not rising from the floor. Her hands were empty, her wrench out of reach. "You underestimated the tensile strength of third-generation piston seals." "I don't need models anymore! I just need two corpses and a signature from the probate court!" The bunker door blew off its hinges. The heavy iron portal flipped through the air, crashing into the masonry wall with an explosive bang that sent pulverized brick across the floor. Through the dust strode a platoon of twelve Dominion Enforcers, their heavy riot shields raised, repeating crossbows leveled in tight, military discipline. Behind them, panting like an overdriven donkey and clutching a mountain of parchment ledgers against his dirt-streaked cravat, stood Drusian Pendar. Drusian’s powdered wig was missing. His aristocratic coat was ripped at both elbows, and his spectacles hung crooked across his nose, but his finger pointed forward with trembling, vindictive triumph. "Drop the weapon, Yvan!" Drusian yelled, his voice cracking on the final syllable. "Drop it! By the authority of the Ministry of Internal Revenue and the Supreme Court of Patents! Every single one of your shell accounts has been seized!" Yvan froze, the pepperbox trembling in his grip. "What? What is this? Drusian, you idiot boy, you have no jurisdiction—" "I have the promissory notes!" Drusian shrieked, waving a ream of water-stained receipts. "The bribes to the smelting inspectors! The illegal land grabs! And the half-million sovereigns you borrowed from the Merchant Syndicate using my family's name as unauthorized collateral! You ruined me, you old vulture! You spent my political inheritance on saboteurs!" The Enforcer sergeant stepped forward, slammed the butt of a halberd across Yvan's wrist—shattering the bone with a sharp crack—and kicked the pepperbox across the floor. Two more Enforcers drove Yvan to his knees, clamping heavy lead-lined irons around his bleeding arms. "Let go of me!" Yvan howled, twisting violently as they hauled him toward the ruined doorway. He glared back at Sybilla, spitting blood onto the stone. "You think you've won? You think this ends here? That little idiot cousin of yours—she told me! She told me how the empire falls! She knows every market crash! She knows the future! You'll starve in this dirt!" Outside in the corridor, sitting in a puddle of stagnant drain runoff where she had been abandoned, Cosmina Korvesk pulled at her mud-caked lace sleeves. She looked at Drusian, who was furiously blowing his nose into an unpaid tax lien, and then looked into the bunker at Corso Fennick, resting against Sybilla with a patent-making war machine still smoking on his arm. Cosmina buried her face in her filth-covered hands and let out a piercing, hysterical wail. "I picked the wrong husband!"

Calculating the Human Element