A dull haze lingered over Eternium as dawn's artificial light glimmered against the towering fortress walls, steel barriers that had sheltered humanity for centuries. High above the Lower Tier, Valen sat on a precarious metal walkway, letting his legs dangle over the edge. He liked this vantage point; it gave him a moment of calm before the city's clang and clamor erupted into full gear. Machinery thrummed in the distance, hauling cargo and supplies through a maze of platforms and scaffolding. Neon signs advertising "Filtered Water" or "Ration Exchange" flickered below, lighting up cramped corridors where Lower-Tier residents hustled to eke out a living.

Valen drew in a breath of acrid air—a blend of burning trash, stale oxygen, and the faintly electric tang of Eternium's energy barriers. Home was never supposed to smell pleasant, but it was what he knew. A tattered satchel rested against his hip, heavier than usual. Dr. Suri had handed it to him earlier that morning with a cryptic warning to be careful. He suspected it contained more than just the usual logs and minor lab gear; the clinks and rattles told him there might be samples or tech inside.

He rose to his feet and slung the satchel over his shoulder just as a familiar voice called out. Rune, all lanky limbs and wild hair, sprinted across a narrow catwalk connecting to Valen's perch. He skidded to a stop, leaning on a railing to catch his breath.

"I've been searching everywhere for you!" Rune gasped. "Captain Orley's people posted a notice: they're rounding up volunteers for the perimeter again. Something about bigger mutants outside the walls."

Valen tightened his grip on the satchel. "So the rumors might be true?"

Rune nodded, eyes darting toward the fortress skyline. "Word is a scavenger crew got ambushed last week. Only two survivors, half-crazy. They claim the zombies were… organized. But, you know, rumors."

Organized zombies. The idea made Valen's skin crawl. Zombies usually lumbered in mindless hordes; if they were actually working together, that spelled a new level of danger. He glanced at the monolithic walls bristling with cannons and searchlights. The city had kept threats out for centuries, but everything eventually wore down—steel included.

"Let me drop off Dr. Suri's package first," he said, mustering a calm he didn't entirely feel. "Then I'll check out those postings. You thinking of volunteering?"

Rune shrugged. "Double rations can't hurt. If we don't sign up, someone else will. We both know the city needs every warm body it can get these days. Anyway, I'll find you later."

He dashed off as quickly as he came, leaving Valen to navigate the descent into the Lower Tier. Twisting ladders and rusted staircases led him past rickety stalls where vendors hawked oily soup and bootleg water filters. Families crouched near sputtering heaters, their eyes hollow with fatigue. A short broadcast rattled from overhead speakers—some standard cautionary message urging residents to report suspicious activity. It sounded more urgent than usual.

Eventually, Valen arrived at a squat, reinforced building marked with Ravika's Lab sign. Two mismatched guards let him pass after checking the emblem on his satchel. Inside, dim fluorescents highlighted scuffed metal floors, and the air reeked of disinfectant. A petite technician intercepted him, eyes flicking nervously between him and the bag.

"You from Suri's unit?" she asked. He handed over the satchel. She looked inside and swallowed hard. "Gene splicing protocols, Infectivity analyses… Strain 92? Damn. Follow me."

They moved deeper into a cluttered chamber ringed by half-dismantled machines, beeping monitors, and rows of sample cylinders—some containing grotesque lumps of mutated tissue floating in a murky solution. Valen tried not to stare too long at the severed limbs and half-formed faces pressing against the glass.

The technician spread the lab materials out on a steel worktable, scanning labels on sealed tubes. "We might have a lead on slowing certain mutations. If we can figure it out, it'll reduce new horrors spawning out there… maybe." She let out a weary sigh. "Sometimes it feels like we're plugging holes in a sinking ship. How much did Suri tell you?"

"Nothing," Valen admitted, hands shoved in his jacket pockets. "Just to deliver it safely."

"Typical." The technician handed back the now-empty satchel. "Thanks, anyway. Watch your step in the Lower Tier. We've had sightings of creepers near the west wall. That's not normal."

Valen nodded, trying to quell the knot in his stomach. On the way out, he passed glass cylinders holding twitching zombie remnants: half a torso, jaws slack, milky eyes blinking as if still alive. Even with centuries of research, no one truly understood how the virus combined with radiation to create these abominations. His own reflection wavered in the fluid, an unsettling reminder that any slip-up—an infection, a breach in the walls—could turn someone into that.

The lab doors hissed shut behind him, and he found himself back in the labyrinth of Eternium's lower corridors. He started to climb one of the spiral walkways to return Dr. Suri's satchel when a deafening crack rippled through the air. The steel walkway beneath his feet trembled, metal groaning as if struck by a distant shockwave. Voices shouted from below, some in panic, others in confusion.

He gripped the railing, heart hammering. No alarms sounded, so it wasn't a direct breach, but it had to be close—a collapse or explosion in the Dead Zones. Such tremors didn't always mean an attack, but they served as a grim reminder: they were never truly safe. If the city's defenses failed even once, Eternium could fall in a day.

Flint, a grizzled ex-mercenary Valen vaguely knew, appeared at a nearby cargo lift, hefting a crate onto it. He caught Valen's eye and gave a brusque nod.

"Heard you're a runner for Suri," Flint said. "That's good. Means you can handle yourself in a pinch, right?"

Valen's laugh was hollow. "I just deliver stuff. Not sure that qualifies me for anything else."

"Might need every spare hand on the perimeter soon," Flint grunted. "We keep hearing about organized packs out there. If you see or hear anything, don't sit on it. Let someone know."

Valen watched him punch the lift controls. Flint's usual swagger was overshadowed by a tense urgency. When even hardened mercs looked uneasy, it was a bad omen. Valen waved a silent goodbye and turned back toward the path leading to Dr. Suri's lab. He'd heard enough rumors for one morning, and the thunderous echo still rang in his ears.

Overhead, the city's artificial lighting shifted, indicating midday. Below, he glimpsed the Lower Tier's daily grind continuing: children clustering around a communal water tank, merchants haggling over battered rifle parts, guards patrolling with harried expressions. Everyone wore the same weight on their shoulders, an unspoken dread that someday the walls—those silent monoliths that gave them peace of mind—might fail.

He paused on a rusted skybridge. His reflection hovered in a broken panel of plexiglass, faint and ghostlike. Part of him wanted to stay a mere courier, safe in routine errands, but another part bristled with questions. What if the rumors about organized zombies and advanced mutations were true? If the labs were onto something, maybe that knowledge could protect them all—or unleash a new nightmare.

His grip on the empty satchel tightened. Somewhere out in the Dead Zones, monstrous creatures roamed. This city relied on tall walls and half-forgotten technology to keep them at bay. If something managed to unify those scattered beasts, Eternium would face the fight of its life. And here he was, just a runner caught up in the middle, uncertain how to help—or even if he could.

A final look over the edge reminded him how precarious life in Eternium truly was. Corridors, shops, living quarters—everything stacked in a haphazard sprawl that seemed indestructible from afar yet felt alarmingly fragile up close. He didn't realize he'd been holding his breath until he exhaled, letting the tension slide off his shoulders for a moment.

At least for now, the city stood. If that thunderous rumble meant anything, it was a warning of what might come. Valen resumed his walk, the clang of his boots echoing against metal slats, each step heavier than the last. The words "organized zombies" lingered like a stubborn echo in his mind, and no matter how hard he tried, he couldn't shake the feeling that something far worse lay waiting in the darkness beyond the walls.

Either way, the weight of those walls was pressing down on everyone. And Valen wasn't sure how much longer they could hold.