GRENUN: When The Air Killed Us

Chapter 15: The Scrubber Core

The steel structural truss beneath the railway bed is a narrow, suffocating tunnel of rusting iron girders and crisscrossing support struts.

Fifty feet below my boots, the Baltic sea surge churns through the drowned industrial basin, throwing cold spray up through the open iron grating. The dark current hits the bridge’s concrete pylons with a heavy, rhythmic thud that vibrates straight into my chest, making my teeth ache inside my facepiece.

*SKRRR-HHHH. SKRRR-HHHH.*

Every drag of oxygen through my Dräger respirator feels like dragging dry sand across raw flesh. Sweat drips continuously down my forehead, pooling in the bottom rubber seal around my chin, sloshing with every frantic step. The lower glass viewports of my mask are half-fogged with sweat and condensation, forcing me to tilt my jaw up just to keep Mara’s dark, water-dripping tactical boots in sight three yards ahead.

Mara crawls through the hollow iron beam on her hands and knees, her 12-gauge shotgun strapped flat across her back. Her black coat streams with sea spray, her leather-gloved hands gripping the wet, sharp-edged iron flanges to keep from being thrown off by the gale-force coastal wind.

I drag myself behind her, clutching the yellow emergency box tightly against my ribs with my left arm. The hard plastic casing is freezing cold, covered in a thin sheet of white frost that numbs my fingers through my leather glove.

`WARNING: CORE TEMPERATURE CRITICAL`

`REGEN-4 NEUTRALIZER MATRIX: PURGE MODE`

`BATTERY LIFE: 39:48:12`

`AIRBORNE SCRUBBER RADIUS: 4 METERS`

The digital monitor set into the top of the case flashes a violent red warning. The blue light leaking through the sealed plastic seam has narrowed into a faint, sickly pulse—a weak indigo glow that barely pushes past my boots. The five-meter purification bubble is shrinking with every second we spend inside the iron truss.

Above us, through the gaps in the wooden rail ties, the three transformed Regen Enforcers are walking across the tracks.

*CLANG. CLANG. CLANG.*

Their heavy combat boots strike the iron rails in perfect, terrifying synchronization. They aren't rushing. They don't need to. They walk with the steady, unhurried pace of machine clockwork, their grey tactical suits gleaming wetly under the ash-covered sky.

And through the wooden ties, their hum descends into the hollow truss.

*Schlaf, Kindlein, schlaf...*

*Der Vater hütet die Schaf...*

The lullaby doesn't travel through the air as sound—it travels through the structural steel as a high-frequency acoustic wave. The iron girders under my knees begin to sing, vibrating against my leg bones until my marrow shudders with the tune.

A sharp, violent pain spikes behind my eyes. My hands shake so badly I nearly drop the yellow case down through the iron grating into the churning sea water below.

*No,* I bite down on my tongue until I taste warm copper, using the physical pain to shatter the hypnotic static crawling up my brainstem. *Focus on the box. Focus on the filter.*

Through the wooden ties above my head, a thick, concentrated curtain of pale green vapor begins to pour down through the gaps, cascading like toxic steam into the hollow space where we crawl.

The green mist hits our four-meter indigo bubble, making the yellow box emit a high-pitched, screaming whine as its internal cooling fans fight the high concentration of aerosol.

"Silas!" Mara yells back over her shoulder, her voice crackling through her mask speaker. "The fog is cutting off the truss exit ahead! The scrubber isn't pushing it back fast enough!"

I raise my head, squinting through my wet viewports.

Twenty yards ahead, where the iron trestle anchors into the granite cliff of the industrial ridge, the green vapor has pooled into a solid, impenetrable wall of yellow-green haze. It hangs stagnant in the mouth of the bridge support, three feet deep, completely blocking the narrow iron ladder that leads up to the elevated signal station.

If we crawl into that pocket, our remaining indigo bubble will be instantly overwhelmed. The charcoal canisters on our faces will saturate in less than twenty seconds.

"The manual purge!" I shout into my facepiece, my voice coming out as a strained, wet bark—*phut-clack*. "I have to unseal the core housing! Flush the matrix at maximum output!"

Mara turns her head, her hazel eyes locking onto mine through her water-slick viewports. "You said breaking the housing burns out the battery!"

"If we don't break it now," I yell back, "we won't survive the next thirty seconds to care about the battery!"

Mara doesn't hesitate. She shifts her weight on the wet iron beam, unslings her 12-gauge shotgun, and points the barrel upward through the wooden rail ties above her head.

"Do it!" she snaps. "I'll cover the tracks!"

I drop flat on my stomach across the iron grating, shoving the yellow emergency box into the narrow space between my ribs and the wet steel flange.

With trembling, numb fingers, I grab the heavy brass latches on the sides of the case.

*SNAP.* *SNAP.*

The latches pop open. I grab the heavy plastic lid and yank it all the way back, exposing the core to the open air.

The high-density glass and titanium cylinder inside the box doesn't just glow—it erupts.

A blinding, electric-blue flare surges out of the case, illuminating the dark underside of the bridge in a blinding, sapphire flash. The freezing ozone shockwave expands instantly, blowing outward in a violent, ten-meter sphere of hyper-purified cold air.

The pale green mist cascading through the rail ties shatters on impact, its chemical bonds instantly neutralizing into harmless white frost that coats the iron girders in a layer of ice.

`CRITICAL OVERRIDE ACTIVATED`

`CORE INTEGRITY: 42%`

`BATTERY LIFE: 12:05:00`

`AIRBORNE SCRUBBER RADIUS: 12 METERS`

Twelve hours left. I just traded our entire three-day survival buffer for a twelve-meter blast of clean air.

Above us, the three transformed enforcers stop dead in their tracks on the wooden ties.

The cold ozone pulse hits them full force, severing the acoustic resonance carrying through the iron rails. Their synchronized hum cuts off mid-note, collapsing into a harsh, wet rasp as their infected lungs choke against the sudden vacuum of toxic aerosol.

"Now!" Mara screams, kneeling up on the wet iron flange.

She pulls the trigger of her shotgun—*BOOM!*

The heavy slug punches upward through the wooden rail tie, striking the lead enforcer full in the chest. The force of the blast tears through his tactical vest, throwing his massive grey body backward off the open rails. He plummets fifty feet through the air, hitting the churning black floodwater below with a massive splash before being swept away by the current.

"Move, Silas! Move!" Mara shouts, scrambling forward through the blue-lit frost toward the granite ridge.

I grab the freezing titanium handle of the wide-open yellow box, haul the glowing case up against my stomach, and charge forward on my knees across the ice-coated steel grating.

The white frost under my boots is slick as oil, but the clean, ozone-filled air inside our twelve-meter bubble gives my burning lungs a surge of adrenaline.

We hit the end of the iron truss.

Mara vaults out of the hollow beam, her black boots slamming down onto the solid, dry granite ledge of the industrial ridge. She turns around, shoves her arm down into the gap, and hooks her hand under the shoulder strap of my coat, hauling me out of the iron trestle in a single violent pull.

I collapse onto the granite slab, dragging the screaming, blue-flaring yellow box against my knees, heaving deep, ragged breaths through my filters.

*SKRRR-HHHH. SKRRR-HHHH.*

Behind us, the two remaining transformed enforcers stagger to the edge of the railway tracks, their milky white eyes staring down at us through the blue-tinted drizzle. They open their mouths to resume the hum, but the Baltic wind whips across the ridge, scattering their exhaled vapor into the open sky.

They don't follow us down to the ledge. They stand on the high rails like dark, silent sentinels, watching us withdraw into the rocks.

Mara slumps back against the sheer granite cliff, her shotgun resting across her knees, her dark hair plastered to her forehead beneath her hood. Her hazel eyes are wide, fixed entirely on the yellow box sitting open between my boots.

The titanium scrubber core inside the case is white-hot at its base, its glass housing cracked down the middle where the cold ozone meets the damp air.

"Twelve hours," Mara says, her voice low, flat, and devoid of hope through her mask speaker.

I look up at her through my foggy viewports. "What?"

"The screen," she says, pointing a black-gloved finger at the digital readout on the case lid. "You burned through fifty hours of air just to cross a three-hundred-yard bridge."

I wipe my dripping visor with my sleeve, looking down at the flashing red LEDs: **11:58:22**.

"It got us across the water," I say, my voice raspy, barely audible over the wind howling through the granite pass. "It got us to the high ground."

Mara turns her head, looking up the steep, winding access road that climbs out of the granite rocks toward the peak of the industrial ridge.

Three hundred meters above us, towering over the dark pine trees and ruined corporate bio-domes of the upper district, the red-and-white steel skeleton of the regional broadcast tower pierces the ash-filled sky.

It sits untouched by the floodwater, high above the drowned canals of Greifswald. But around its reinforced concrete perimeter, framed against the grey gloom, dozens of thin, pale green plumes of vapor rise into the wind.

The tower isn't abandoned. The infected have already gathered at the top.

Mara slowly pushes herself up to her feet, racking her last remaining shotgun shell into the chamber with a heavy, deliberate *CLICK-CLACK*.

"Twelve hours, Silas," Mara says, turning her back to the sea and looking up the dark road. "Let's go take our broadcast station back."