Kai's hand tightened on the cold iron rung as he began the climb down into the mezzanine shaft. Each rung was slick with condensation, and the barrier's glow above wavered in the shifting steam. Marcel's earlier warning echoed in Kai's mind: "Nothing natural moves this deep without leaving scars."
Ellie followed, repeater clipped to her belt, its scanner beam illuminating jagged concrete below. "Watch your footing," she advised, her voice steady even as water dripped from overhead pipes. "These stairs haven't borne weight in weeks."
Mara and Theo brought up the rear, boots clanging against metal, ready to deploy mini-barrier patches at the first sign of destabilization. Sentinel hovered just beneath the hatch, barrier narrowed to a cone that lit the way down.
At the mezzanine landing, the air turned noticeably warmer—stale and metallic. The narrow corridor stretched ahead, lit only by Sentinel's beam and Ellie's augmenter. Service conduits lined the walls; many were severed or corroded, and every drip pooled in dark, oily patches on the floor.
Kai knelt to inspect the nearest hatch. "We need to seal this," he said, peeling a barrier patch from his pouch. He pressed it to the fractured seam above the inspection port; it hummed as it adhered, forming a slim dome of protective light.
Ellie crouched beside him. "Good. Now the others—fast." She swept her beam along the corridor as Mara and Theo raced ahead, slapping patches onto each vulnerable hatch and conduit splice in turn. The corridor filled with tiny domes of gold and turquoise light, each guarding against aftershock or Rift-born incursion.
They reached the second service ladder descending to the track level. Kai looked up at the narrow shaft's dark mouth. "Below this, the real test begins." He slid a tether line through a pulley bracket. "I'll go first—Ellie, bring up the rear."
With a nod, they clipped in and began the descent. The echo of dripping water and distant raptor calls filled the shaft. Kai's vines pulsed, sensing each crack in the concrete as he lowered himself into the gloom. Sentinel's barrier ribbon followed him down, a lifeline of living light.
At the bottom, the tunnel opened onto the deserted platform. Graffiti-scarred columns lined the edges, and a single overturned train car lay across the tracks, roots and vines crawling through its broken windows. The air smelled of rust and ancient mold.
Ellie stepped beside Kai, her HUD marking residual Rift energy—weak but present. "We've got readings near the far wall," she said, pointing. "Let's move."
They crept along the platform's edge, deploying small sensor beacons at five-meter intervals. Each beacon pulsed green as it harmonized with the barrier seeds aboveground. Mara and Theo trailed, carrying extra moss-cord for any crack that dared to bleed Rift memory.
Halfway to the target wall, the platform shuddered. A low hum vibrated in the rails. Kai froze, vines tightening reflexively. Ellie's repeater chimed: Transient spike—0.6 magnitude.
Mara's barrier patch flickered. Theo steadied it with a quick press. "Not bad," Kai murmured. "This level is shaking less than aboveground."
Ellie scanned the far wall: a fracture ran from ceiling to floor, jagged and dark. "That's our entry point," she said. "Careful—this one's old."
Together, they approached, sensory beacons casting long shadows. The Rift's echo whispered from behind the crack, faint whispers of memory that Kai could almost make out—a child's laughter, a train conductor's call, the rumble of a steam engine.
He swallowed. "We're here."
Ellie placed a moss-seed at the fracture's base. It pulsed gold, then green, anchoring itself in the concrete. Mara and Theo pressed into the seam, weaving a living cord that glowed steadily. Sentinel's barrier dome expanded to cover the entire fracture, the light cutting through the whispering echoes and holding them at bay.
Kai exhaled. "Seed's active. Let's map the next section."
Ellie tapped her repeater, overlaying tunnel schematics on her HUD. The route deeper into the station branched into three corridors—each more shadowed than the last. She pointed at the middle passage. "That one leads to the maintenance hub. We should check power status and cross-reference Rift energy readings there."
Kai nodded. "Routine first, then progress."
With the fracture secured behind their living lattice, the four ventured down the chosen corridor, Sentinel's barrier guiding them into the unknown depths—ready for whatever echoes the Rift had left waiting below.
They stepped into the middle corridor, Sentinel's barrier narrowing to a focused conduit of light along the rough concrete walls. Ellie's augmenter cast a pale glow, revealing rusted control panels and broken cable trays overhead. The air was stale, tinged with the scent of burnt insulation.
Kai led, vines stirring beneath his sleeves as he brushed aside hanging wires. "This way," he murmured, following the HUD's overlay as it guided them toward the maintenance hub. Each beacon they'd planted pulsed softly on the screen, a breadcrumb trail in the gloom.
After fifty meters the corridor opened into a vaulted chamber—the old switching yard. Massive circuit breakers loomed in half-melted rows, their ceramic insulators spider-webbed with Rift residue. Ellie knelt at the nearest breaker, sweeping her repeater across its housing. "Energy residue at forty percent of aboveground levels," she reported. "Not enough to trigger a flare, but enough to interfere with long-term stability."
Mara and Theo moved to the opposite side, placing moss-cement packs into fractured junction boxes. As they worked, a distant clang echoed through the chamber—metal on metal, slow and deliberate. The four froze, barrier patches flaring in warning as Sentinel's beam spun toward the sound.
Ellie's voice was tight. "That came from the eastern access shaft." She tapped her HUD. "Footprints—fresh. Not raptor; too humanoid."
Kai exchanged a look with Mara. "Keep reinforcing the junctions," he ordered. "Ellie, Theo, check that shaft. I'll cover you."
Ellie and Theo approached the eastern exit; vines subtly braced the cracked floor beneath each step. Sentinel's barrier contracted into a defensive dome around them as they peered down the shaft: a ladder worn smooth at the rungs, trailing wires that led upward into darkness. Halfway up, a length of moss-cord lay severed—its living fibers wilted and blackened.
Theo swallowed. "Someone's been here—cut through our defenses."
Ellie drew a breath and stood tall. "Then we find out who—and why." She stepped onto the lower rung, the barrier expanding overhead, vines glinting in Sentinel's light.
Kai stayed below, vines tensing as he watched the pair ascend. Mara moved beside him, checking the junction's stability gauges. The hum of the enclave's distant heartbeat felt suddenly far away, eclipsed by the uncertainty lurking in the abandoned service shaft above—and by the knowledge that, somewhere beyond the seeds and barriers, an unseen presence was watching their every move.
Ellie's foot hovered over the next rung as the ladder creaked under her weight. Theo illuminated the shaft walls with his goggles, revealing scrawled markings—faded symbols that pulsed faintly with leftover Rift energy.
"Look at these," Theo whispered, tracing one symbol with a trembling fingertip. "They're not our designs—something else carved them."
Ellie's jaw set. "Whatever's down here doesn't just repurpose our defenses; it's rewriting the station itself." She climbed silently, barrier contracting into a tight sphere around her and Theo.
Above, Kai watched the hatch's edge, vines sliding across the metal to reinforce each bolt in anticipation. Sentinel's barrier guarded the chamber entrance, ready to block any intruder ascending. He could hear every click of the ladder rungs and the distant drip of condensation—it was too quiet, and that quiet felt alive.
Ellie reached the midway landing and pressed her palm to the wall, the repeater humming. "Residual energy surges ahead," she reported, voice flat. "Follow me." She led Theo through a service door at the landing, stepping into a narrow catwalk overlooking the flooded track bed.
A single spotlight flickered in the gloom as water lapped against submerged rails. In its beam stood a silhouette—tall, armored in rusted panels, and carrying something that glowed with the same oil-thin sheen as the memory-fog.
Theo gasped. "What is that—?"
Ellie raised a hand. "Don't move."
The figure turned, revealing a featureless mask fused to its helmet. Where eyes should have been, there were only dark hollows. It raised an arm, and in its gauntleted hand was a shard of the shattered symbiote tank—a trophy, still dripping with distilled memory.
Ellie's voice was steel. "You took our seed network, corrupted it—and now you mock us."
The figure tilted its head as if to listen, then strode forward on the catwalk, water rippling at each step. Theo fumbled for his mini-barrier; Ellie caught his arm.
"Wait for my mark."
Below, Kai braced himself, vines coiling into living shields around the hatch. Sentinel's barrier pulsed, straining against the hatch's frame as if sensing the approach of something far more relentless than any breach surge.
High above in the flooded station, Ellie whispered, "On three—"
A distant roar rolled through the tunnels, and in that moment, all their careful routines snapped taut against a new, dark rhythm.
As the roar echoed through the flooded station and the armored figure advanced, Kai felt Sentinel's dome tighten, vines bracing the hatch against an onslaught they'd never faced before. Ellie and Theo hovered on the catwalk's edge, hearts pounding as the dark specter of memory and malice descended.
In that charged silence, every drill, every seed, every patch laid in careful routine converged on this moment of truth. And beneath the humming barrier, brother, sister, and sentinel steeled themselves for the breach's most intimate assault yet—knowing that their next choice would shape Meridian's fate.