The echo had returned.
But this time, it wasn't fading—it was moving.
Lu Zhen froze mid-step. Yue Fei had just taken point around a broken support beam when her hand raised in a clenched signal: halt.
From the darkness ahead, a low screech rolled across the tunnel. Not a roar, not a shriek, but something wet and gurgling—infected.
Lin Xia whispered, "That sound—there's more than one."
Lu's HUD pinged.
[Hostile Signature Detected – Class E Infected]Proximity: 23 metersEstimated Count: 3–4Threat Level: ManageableLight Response: Aggressive under flickering sources
He tightened his grip on the shotgun slung on his shoulder. "Stay close to the walls. Kill zones in the center."
The flickering light module overhead buzzed and blinked—twice, then dimmed.
Out of the dimness, the first one appeared.
It skittered on all fours, mouth twisted unnaturally, body hunched like a broken marionette. Flesh peeled from its jawline. Its eyes—once human—now glowed faintly with bluish haze.
Yue Fei didn't wait.
She dashed forward, blade angled low. As the infected lunged, she slid under its swipe and slashed upward across its abdomen. Black-red fluid sprayed the concrete as its insides split open. The creature convulsed, then collapsed with a wet, twitching thud.
But its screech had summoned the others.
From a side shaft, three more figures emerged—running, limbs flailing erratically.
"Four o'clock!" Lin yelled, raising her knife.
Lu stepped forward, planting his feet.
The shotgun roared once.
The slug struck the lead infected in the sternum. Its chest erupted outward in a blossom of bone and gore. The body lifted off its feet and slammed into a pillar, leaving a dark smear on the wall.
A second infected barreled toward Yue from the side. She spun, kicked its knee to unbalance it, and drove her blade under its chin—forcing it upward until the tip pierced out through its skull.
She let the body drop without a word.
The third infected lunged at Lin.
Her arms froze—just for a moment.
Its claw grazed Lin Xia's shoulder, forcing her back against the wall. The infected raised its other arm for a killing blow—
—but Yue's pistol cracked through the air.
The shot hit clean between the infected's eyes. It stumbled backward, dropped like dead weight, and twitched twice before falling still.
Lin blinked, breath caught in her throat. "T–Thank you…"
Yue didn't even turn. "Don't freeze again."
Lu stepped beside Lin and pulled her back. "You good?"
She nodded slowly, eyes still wide. "Yeah... I think so."
"Then don't stop moving," he muttered. "We're not done yet."
From deeper within the tunnel, a new echo answered. Sharper. Faster.
More were on the move.
Lu grabbed a bundle from his pack—a cylindrical device built from a modified speaker coil and battery. He slammed it against the wall and activated it.
[Deploying Sonic Trap – Frequency Pulse Active]→ Decibel Range: 14kHz – 17kHz→ Duration: 15 seconds→ Effect: Disorientation in Class E Infected
A high-pitched shriek filled the air. The remaining infected paused, twitching violently. One of them clawed its own ears. Another slammed into the wall repeatedly.
"Now!" Lu shouted.
Yue rushed forward. Her blade struck low—hamstringing the creature. As it fell, she stepped over and stabbed clean through its eye socket.
Lin, regaining her composure, lunged at the last one, stabbing into its ribcage. The blade jammed, but she twisted it with a grunt and pushed the infected backward until it collapsed.
She stared at the body, chest rising and falling rapidly.
"I... I killed it."
Lu approached slowly. "It was going to kill you first."
"I know. But still... it feels different."
Yue patted her shoulder roughly. "You survived. Process the rest later."
Suddenly, a HUD ping.
[Phoenix Rig – External Seismic Alert]Source: Shotgun Blast ReverbStatus: No Hostile Contact DetectedSystem: Back to Standby Mode
Lu exhaled. "RV's alarm was triggered. Probably from the blast echo. No danger."
He walked over to the last infected that was still twitching faintly. He raised the shotgun, took aim at its upper chest, and fired one last time. The spread blew through the creature's ribs, and it slumped back—dead for good.
Silence returned—only the drip of water and the hum of HUD modules remained.
They took a moment to regroup.
Yue wiped her blade on her leg. Her shoulder armor was scratched, a chunk of her outer jacket torn where the infected had grazed her.
"You hurt?" Lu asked.
"Not enough to matter."
He checked Lin's arm—light bruising, no break.
"We're fine. That's what matters."
Then Lu crouched beside one of the fallen infected. Its body had mutated in strange ways—muscles knotted unevenly, bones protruding.
Yue joined him. "Whatever's doing this… it's still evolving."
"Or adapting," Lu said darkly.
He checked his shotgun. Two shells left. Barrel slightly warm. Recoil had bruised the edge of his palm.
"Shotgun's solid. Need to refine the grip. But it works."
"Better than expected," Yue admitted.
They started to move again—more alert now, blades out, spacing tighter.
Five minutes later, they reached a rusted emergency access door. Beyond it was a side corridor leading back to the main tunnel loop.
But something else caught Lu's attention.
A broken maintenance terminal blinked faintly. He connected his HUD.
[Data Packet Recovered]→ Partial Blueprint Unlocked: Shock Trap v0.2→ Status: Locked (Craft Lv.3 required)→ Effect: Delayed detonation based on pressure or proximity trigger
He saved it without a word.
"Blueprint?" Yue asked.
"Could help slow them down next time."
They made their way back toward the Phoenix Rig in silence, every sound amplified in their ears now.
When they reached the RV, it stood exactly where they left it—untouched, silent.
Lin climbed in first, collapsing onto her bunk.
Yue remained near the doorway, blade still in hand.
Lu glanced at her. "Can't rest?"
"Just... listening."
"To what?"
"To the fact we made it back. Alive."
He smiled faintly. "And together."
Then the door sealed behind them, locking out the echoes once more.