The Cost of the Crossing

The mess hall smelled of burned flux, stale chicory, and the sour, thinning bite of air that had been through a dying scrubber three times too often.

Murchadh dropped his brass micrometer onto the galvanized prep table. The tool clattered against the zinc plating with a heavy, solid ring, but neither of the others flinched. Across the narrow room, seated beneath the buzzing amber tube of the secondary emergency light, Riosbh had spread out eleven scorched circuit boards and three waterlogged binders of corporate safety directives. Her fingertips were black with soot, her pale hair coming loose from its regulation clip and sticking to the sweat on her temples.

"The relay sweep runs on an automated twenty-four-hour cycle," Riosbh said, her voice strained to a thin, stubborn rasp. She tapped a charred fiberglass board with the blunt end of a pencil. "If the core array burned out during the surge, the orbital platform logs the signal drop as a Category Two hardware anomaly. That triggers a mandatory unmanned telemetry drone within forty-eight hours. Paragraph Six, Subsection Twelve. If we are not inside the designated shelter envelope when the drone sweeps the beacon coordinates, the recovery contract is voided."

Murchadh wiped a streak of hydraulic sludge from his cheek with the back of a canvas-wrapped forearm. "The drone isn't coming, Riosbh."

"You cannot know that," she snapped, not looking up from her papers. Her pencil dug into the damp pulp of the manual until the graphite snapped. "The protocol is automated. It does not require administrative sign-off from Ness. The relays fire independently of sector evacuation orders."

"The relays fire if the orbital platform has power to send them," Murchadh said. He picked up his calipers, adjusted the screw with a flick of his thumb, and pointed the steel tips toward the ceiling. "Colmhaign burned the station's step-up transformer into a lump of melted slag to keep the scrubber running for twelve hours. When that transformer blew, it back-fed twelve thousand volts into the main junction box. Look at the conduit run above your head."

Riosbh hesitated, her chin lifting slightly.

The conduit casing was blistered and split like cooked sausage casing, black carbon scoring fanning across the ceiling ribs in wide, greasy plumes.

"The secondary capacitors took the jolt," Murchadh continued, his voice low, measured, and flat with five years of maintenance fatigue. "The high-gain mast on the roof didn't just lose signal. The base insulators shattered. If an orbital drone flew three meters above the cupola right now and shouted down our throat, all it would hear is dead iron."

"Then we repair the ground mast," she insisted, her voice climbing half an octave. "We have spare copper leads in the tool crib. We have three spare relay boards in the avionics locker."

"The tool crib is under three feet of acidic mud and alien mineral growth," Murchadh said. "I left my best torque sets and two cases of sealing compound down there, and right now they are encased in a solid block of Vaeluigh crystal that eats drill bits for breakfast."

He turned away from her, unwilling to watch the panic flutter behind her red-rimmed eyes, and focused his attention on the mess hall's emergency bulkhead.

Colmhaign stood by the narrow airlock vestibule at the far end of the compartment. He had already stripped out of his vulcanized outer canvas, wearing only his grease-stained woolens and high leather boots. His broad shoulders were hunched slightly under the low steel ceiling beams as he systematically laid out three field packs on the floor plates. In the dim amber glare, the deep burn scars on the left side of Colmhaign's neck looked like knotted rope. He did not join the argument. He simply continued sorting mechanical fittings, brass valves, and compressed ration bars with the rhythmic, unhurried precision of a quartermaster loading a funeral barge.

That quiet competence irritated Murchadh almost as much as Riosbh's frantic denial.

Murchadh took his brass-headed hammer and tapped the rim of the mess hall intake vent. The sound was dull, choked, and entirely wrong. A healthy duct rang with a clean, high acoustic pitch. This one gave off a wet, muffled thud, like striking a waterlogged timber.

He took a small notebook from his breast pocket and uncapped a grease pencil. His hands were thick-knuckled, scarred by three decades of hot steam lines and stripped threads, but his handwriting was neat and tiny.

"Habitat core volume is ninety-six cubic meters," Murchadh muttered aloud, checking his numbers against the bulkhead pressure gauge. "Three adult occupants at rest consume roughly forty-two liters of pure oxygen per hour. Call it one point two six cubic meters per day for the three of us combined. With the bypass Colmhaign jammed into the scrubber, we should have held fifty kilopascals of partial pressure for ten hours, easy."

He stopped, pressing the cold brass caliper tips against the rubber gasket lining the intake collar.

The rubber felt greasy. Not with machine oil, but with a thin, slick coating that smelled faintly of rotting vinegar and wet chalk. He rubbed his fingers together; the rubber disintegrated between his pads into a sticky, black paste.

"The growth in sublevel one is drawing three times our metabolic rate," Murchadh said, turning back toward Colmhaign. "The litmus test from the basement wasn't lying. That amber plug over the drainage sluice is breathing station air to build its mineral lattice. It's pulling oxygen through the floor drains and exhausting carbonic acid back into the returns."

"Six hours," Colmhaign said without looking up from a coil of braided hemp rope. "Seven if we sit on the deck, close our mouths, and do not light a heater."

"Then we cut off the basement," Murchadh said immediately, stepping toward the center of the mess hall. His instincts as a maintenance chief kicked in, rigid and defensive. "We drop the steel drop-gates on the vertical shafts. I have an oxy-acetylene torch in the emergency locker behind the pantry. We weld the shaft coamings solid. We slap cold-rolled steel plate over the four floor grates and cinch them down with lead wedges. We isolate this level entirely. Thirty square meters of living space. We seal ourselves in, run the scrubber at minimum flow, and wait out the barometric surge."

"And when the Breath-Tide peaks in four hours?" Colmhaign asked. He picked up an iron shackle, inspected the threading on the pin, and dropped it into a heavy canvas rucksack. "The external barometric pressure will rise to three hundred kilopascals. What holds the outer seals?"

"This station was engineered for four hundred," Murchadh countered, his chest tightening. "The outer skin is double-walled titanium-alloy plate with high-density polyurethane insulation between the ribs. It stood through the winter gales three seasons back."

"The structure will hold," Colmhaign said calmly. "The seals will not."

"I inspected those seals myself during the last turnaround!" Murchadh's voice rose, the professional pride of five thankless years flaring hot in his throat. "Silicone-neoprene matrix, cold-molded, tested to five atmospheres of hydraulic shear! Don't tell me my gaskets won't hold air, Colmhaign. You were in command of logistics on the southern front, not the mechanical division."

Colmhaign stopped. His scarred hands rested flat on the top of the canvas rucksack. The silence in the mess hall stretched out, heavy and thick, punctuated only by the wet, rhythmic rattle of the dying scrubber in the ventilation trunk.

"Riosbh," Colmhaign said quietly.

The botanist jumped, her shoulders stiffening. "What?"

"Go to the reserve gear locker beside the outer airlock," Colmhaign said. "Bring out the Mark-Four composite environmental suit. The unissued one in the crate."

Riosbh blinked, looking between Colmhaign and Murchadh. "That's reserve gear. It has a factory integrity seal on the crate latch. If we break the seal without an active decompression emergency, the equipment write-off comes out of our base pay."

Murchadh let out a sharp, ragged bark of laughter. "Go get the crate, Riosbh. If we die of hypoxia by midnight, I promise you corporate won't find a payroll office willing to invoice your ghost."

Riosbh hesitated, then shoved her chair back with a scrape of aluminum legs. She disappeared into the short access corridor toward the airlock. A moment later, the hollow sound of latch bolts being wrestled open echoed through the bulkhead, followed by the dull drag of a heavy polyethylene container across the deck.

She returned carrying a sealed olive-drab plastic case, setting it heavily on the prep table between Murchadh's calipers and her burned circuit boards.

Colmhaign walked over to the table. From his leather field kit, he took a thick-walled glass sample jar. Inside the glass, floating in two inches of murky yellow condensation, was a three-inch lump of dark, fibrous sludge Colmhaign had chiseled from the sublevel breach an hour before. The mass did not move, but tiny amber needles bristled along its edges, catching the light like crushed glass.

"Open the crate," Colmhaign said.

Murchadh reached over and cracked the plastic shipping seals with his thumb. Inside, nestled in molded grey foam, lay the pristine Mark-IV composite transit suit. It was the pride of corporate procurement: immaculate snow-white polymer weave, flexible neoprene joint bellows, clear laminated polycarbonate visor, and a high-efficiency synthetic air-purification collar. It had cost more than two years of Murchadh's base salary.

"This is top-tier kit," Murchadh murmured, running his rough fingers over the smooth, vulcanized synthetic thigh piece. "Multi-layer polyurethane vapor barrier. Certified against corrosive vapors and particulate loads up to five microns."

Colmhaign unscrewed the brass lid of the sample jar. The smell that billowed out was sharp, pungent, and electric, like rotting sea kelp mixed with battery acid. Riosbh took an involuntary step back, pressing her hand over her nose.

Colmhaign did not flinch. He picked up a steel laboratory spatula from Riosbh's disarray of tools, dipped the flat blade into the jar, and lifted a single globule of the amber sludge.

"Watch the joint bellows," Colmhaign said.

He touched the spatula to the flexible synthetic fabric at the knee of the brand-new Mark-IV suit.

Murchadh leaned in close, his calipers forgotten in his fist.

For three seconds, nothing happened. The amber droplet sat innocently on the bright white polymer weave, a small brown smudge on pristine material.

Then the droplet spread.