Backblast Salvation

The frost did not crawl across the trench timbers; it struck like iron hammers.

Within ten paces of the central junction, the temperature plunged forty degrees below the zero mark. Seventy upright silhouettes—fifty sealing the northern sap behind the ruins of Redoubt 3, twenty barring the southern revetment—drained every scrap of caloric energy from the corridor. The damp chalk in the duckboards split with sharp, cracking reports. Overhead, the whine of Danubian photolytic shellfire turned dull and distant, swallowed by the acoustic vacuum that bloomed wherever shadow-hulls clustered.

Beside Dorottya, two retreating infantrymen from the Eleventh Line crumpled against the revetment. Their quilted tunics stiffened into brittle armor, frost sheeting across their woolen collars in gray fern patterns before their knees even touched the slush. Their breath did not smoke. In the core of a shadow-corral, there was no ambient warmth left for moisture to condense against.

"Chief," Gyurka croaked. He leaned his broad frame over the sledge's tow bar, his yellow-lint bandages frozen hard as pine bark against his knuckles. "My eyelashes are stuck to my cheeks. Tell me we aren't dying over cold turnips."

"Get behind the iron plate," Dorottya said. Her voice rasped against her wool scarf, the lining of her throat dry as pumice. "Down on the boards."

The remaining four conscripts who still had movement in their limbs tumbled into the bottom of the traverse, huddling behind the sled's quarter-inch boiler-iron deflector shield. Their teeth clattered in ragged rhythms.

Dorottya knelt in the freezing slush. Her knees were numb, but her fingers remembered the clearances.

One lance blast cleared a single silhouette over ninety seconds, expending twenty pounds of slurry and leaving the operator gasping in an oxygen pocket five yards wide. She did not have ninety seconds. She had seventy silhouettes, two hundred pounds of forty-weight aluminothermic paste locked in four fifty-pound cylinders, and less than three minutes before the thermal sinkholes solidified their blood.

Clearing them in sequence was impossible. She had to vaporize the southern wall in a single catastrophic release.

She reached for the three-quarter box spanner at her belt. The cold steel bit through her leather mittens. Leaning over the brass manifold, she located the return-bypass valve she had bolted on twenty minutes earlier in the aid station.

"Hold the manifold casing, Gyurka," she commanded. "If the housing twists while I back out the collar, the feed lines will shear."

Gyurka dropped to his knees in the chalk slush, throwing his chest across the twin brass feed pipes. "Two hundred pounds of forty-weight paste," he muttered through blue lips, his chin wedged over the pressure dials. "Back home, that much tallow bakes three thousand loaves of rye. Or roasts an entire provost staff wagon, horses and all, if someone gives us a roasting pan."

"Hold the brass," she repeated.

Dorottya set the spanner against the locking nut of the return bypass. The threads were already seizing, skinning over with rime. She threw her shoulder into the handle, muscles burning under the heavy sheepskin coat. The nut gave an inch, spitting flakes of frozen graphite grease.

She spun the nut clear and let it drop into the slush. With her copper probe, she jammed the needle into the internal diaphragm housing. The internal brass spring popped, forcing the secondary pressure relief wide open.

Now the siphon had no regulator. When the primary ignition chamber sparked, the fire would not channel down the eight-foot lance nozzle in a controlled eight-hundred-pound jet. It would cycle directly back into the manifold, forcing the burning phosphorus slurry straight into all four fifty-pound supply cylinders at once. A closed-chamber backblast. Fourteen hundred degrees across a thirty-yard frontal cone.

"We have no baffle," Gyurka said, watching her yank the feed line free from the lance stem. His voice lost its mockery, reduced to the raw edge of a man looking into an open flue. "It will drink every lungful of air from here to the sap."

"Cloth in your mouth," Dorottya ordered, stripping her scarf and doubling the wool between her teeth. "Press your face into the boards. When the flare takes, don't breathe until you feel the melt-water hit your neck."

She turned the sledge around on its rusted iron runners, hauling the frame until the open manifold pointed directly at the southern traverse. Twenty paces ahead, the twenty executed Danubian silhouettes stood shoulder to shoulder across the narrow passage, pitch-black voids eating the gray morning light. The chalk revetment behind them had already turned into a wall of solid blue ice.

From the northern trench rim, sixty yards away, the crack of a nickel-plated sidearm echoed through the thin air.

Provost Captain Vésztői stood on the parapet above the collapsed redoubt, his slate-gray woolen coat buttoned tight, his silvered barometer dangling from one gloved wrist. Two provost corporals flanked him, carbines raised.

"Herald Illyési!" Vésztői's voice cut through the frost, level, distinct, carrying the sterile authority of an auditor closing an open ledger. "Step away from the ordnance cart. You are violating defensive containment under General Order 9."

Dorottya did not look up at him. She did not reach for her transit pass.

"Keep your head down, Gyurka," she said around the woolen wad in her mouth.

She pulled the brass phosphorus friction striker from her breast pocket. Hooking the striker ring through the siphon's emergency purge lever, she drove the brass nozzle head into the chalk mud with a kick of her heel to anchor the recoil.

Vésztői raised his arm. "Corporal, fire."

A carbine round cracked against the sled's boiler plate, throwing off a shower of iron flakes.

Dorottya hauled back on the friction ring.

The strike sounded like tearing tin, followed instantly by a hollow, sucking thud as the phosphorus primer met two hundred pounds of pressurized aluminothermic paste.

White fire erupted from the manifold housing. It was not a flame that spread or crawled; it exploded outward with the concussive fury of a coal-dust blast in a sealed mine shaft. Blinding incandescence—fourteen hundred degrees of raw chemical heat—scoured the trench walls.

The air vanished.

Dorottya felt the oxygen ripped from her lungs through her clenched teeth, her chest collapsing inward as if a heavy boot had stepped squarely on her sternum. The radiant heat slammed against her leather coat, scorching the fleece collar to cinder in half a heartbeat. Beneath her belly, the frozen mud turned instantly to boiling soup, water hissing against the sled's iron undercarriage.

Ahead, in the southern traverse, the twenty black silhouettes dissolved. The photolytic hulls shattered into geysers of scalding steam and black carbon rain. The permafrost that had locked the revetment exploded into flying chunks of steaming shale as moisture trapped within the stone reached boiling point in a fraction of a second.

The shockwave roared down the line, blowing the provost sentries off their firing step and tumbling them into the northern crater.

Dorottya lay face down in the scalding mud, temples pounding, veins throbbing behind her eyes as her oxygen-starved brain screamed for air. She forced herself to wait. One second. Two seconds.

A draft of freezing wind whipped down from the open ridge above, tumbling into the vacuum created by the blast.

She spat the scorched wool from her lips and dragged in a burning breath. Cold air flooded her airways, sharp as broken glass, tasting of sulfur and vaporized phosphorus.

Beside her, Gyurka coughed violently, heaving up thin yellow bile onto the sled runner. Behind the shield, three of the four conscripts were groaning, their hands clawing at the steaming chalk. The fourth man lay still, his eyes wide and frozen, taken by the cold before the fire could reach him.

"Up," Dorottya barked. Her hands were blistered beneath her gloves, but her boots found purchase in the boiling slush. "Get on your feet!"

Gyurka staggered up, his broad shoulders trembling as he grabbed the drag ropes of the ruined sled frame. The cylinders were blackened husks, their brass fittings melted into slag, but the sled held their spare tools and rations.

"Where?" Gyurka wheezed, wiping soot from his eyes. "The provosts—"

"The provosts are in the dirt," she said, looking back.

Across the northern junction, Vésztői was rising from the collapsed chalk of the parapet, his slate-gray coat smeared with white ash, his silvered barometer shattered on the rocks below his boots. He drew his nickel sidearm, but the air between them was thick with a churning wall of white chemical smoke.

Dorottya turned south. Where the wall of twenty petrified shadow-corpses had sealed the line, there was now a smoking, blackened breach twelve paces wide. The timbers were charred to coal, the duckboards melted into burning bitumen, opening a ragged tear straight through the wire into the snowy wastes of the outer salient.

"Into the wire," Dorottya said, shoving the foremost conscript ahead of her. "Move!"

They scrambled through the smoking breach, dragging the empty sled frame behind them. Beyond the shattered trench line, the dawn broke in pale gray slivers across the permafrost flats of no-man's-land. Behind them, Sector 9 burned in white chemical fire; ahead, the endless blizzard waited, and every provost in the Hegemony had their names.