The morning haze hung over the shattered skyline like a smothering veil, gray and heavy with the remnants of ash. The roads below were still—no crows, no whispers, not even the wind dared to breathe. The entire city block looked like it had fallen into a coma, and only two shadows moved through it: one limping slightly, the other walking close behind, gaze sharp and unreadable.
Yu Ren wasn't limping out of injury, but from exhaustion. His legs ached from trekking through broken concrete and sidestepping collapsed awnings. His arms were sore from wielding the crowbar he'd used to fend off a malformed runner back near the collapsed parking garage. And mentally? He was fried. The system hadn't spoken since yesterday's alert about "Mutation Imminent: Nearby Hostile." But its silence now felt more ominous than helpful.
Kai, on the other hand, moved like a panther—lean and precise. Not a single motion wasted. Occasionally, he'd glance over at Yu Ren, and once, just once, Yu Ren thought he saw the corner of Kai's lips twitch upward.
That... smile.
Yu Ren narrowed his eyes. "What?"
Kai didn't respond immediately, just looked ahead at the decaying fire escape they were headed toward. "You looked like a squirrel when you were panicking earlier."
"I wasn't panicking," Yu Ren hissed, then grimaced when he realized how high-pitched that sounded.
"Oh?" Kai cocked his head. "Your voice was cracking like a radio with bad signal."
Yu Ren bristled. "I was calculating—strategizing. You think fighting off something with three jaws and a spine for a tail is easy?"
"I didn't say that." Kai gave him a dry look. "But it was cute."
Yu Ren stopped mid-step, nearly tripping over a pipe jutting from the ground. "Excuse me?"
Kai didn't stop walking. "Your expression. Like you were trying to look fierce, but your eyes were screaming, 'Help me, I hate this.'"
"That's not—!" Yu Ren spluttered. "I was focused. You know what? I should let the next mutated abomination take a bite out of you."
Kai turned just slightly. "You won't."
Yu Ren knew he was right, which only made his face burn hotter. "Don't get cocky."
They climbed the rusted fire escape slowly. With each step, the groan of metal echoed across the ruins. It felt reckless—too loud—but the alleyway below was blocked with collapsed beams, and this was the only way into the upper floors of the pharmacy. They were hoping to find disinfectants, meds, maybe painkillers. The system hadn't triggered another supply alert, but Yu Ren trusted his gut more these days than the half-awake AI riding shotgun in his head.
As they reached the third floor, Kai paused. "Wait."
"What is it?"
Kai raised a hand, listening. Yu Ren strained his ears. There it was again—a low, almost wet growl. Not quite human, not quite animal.
"Shit," Yu Ren whispered. "Another mutant?"
"Maybe," Kai said. "Could be residual. Let's move slow."
They entered the building through a cracked window. Inside, shelves were toppled, and dried blood painted the walls in erratic streaks. Most of the goods had long been looted—packages torn open, pill bottles cracked and emptied. But some items remained in the corners, untouched, probably because this floor had been difficult to access.
Kai's flashlight scanned the shelves. "Bandages. Gauze. Iodine."
Yu Ren grabbed them quickly, tucking them into the pack. He found a single syringe of something labeled "Rexifen"—probably an off-brand anti-inflammatory. It might still be usable.
Then the sound came again. This time closer. A slosh followed by a drag.
Kai held out a hand, motioning for Yu Ren to stay low. They moved toward the back room, where the shadows thickened. Kai's fingers tightened around the hilt of the knife on his belt. Yu Ren reached for his crowbar and hated how his hand trembled.
What emerged was not what they expected.
It was... human.
Almost.
A man. Or what had once been one. His limbs were too long, his skin tinged blue-gray like it had been underwater for weeks. Black veins crawled up his neck like branches of rot. His eyes were sunken—no whites, just milky voids. But the thing was breathing. And moaning.
Yu Ren nearly stepped back, but Kai caught his wrist.
"Wait," he whispered.
The creature didn't lunge. It just... slumped forward, dragging itself to a broken chair in the corner and collapsing into it.
"It's not attacking," Yu Ren murmured.
"Not yet," Kai said grimly. "But look at its arms."
Yu Ren did. That's when he saw the infection—clearly halted halfway through. Like something had paused the mutation mid-process.
"System," Yu Ren muttered under his breath. "Scan the target."
Scanning...
[Target: Half Mutated Human]
[Host Status: Mutation Incomplete]
[Host Consciousness: Fragmented]
[Potential Source of Resistance Serum: 23]
Yu Ren's eyes widened. "It's—stable. Like, half-stable."
Kai was already circling the edge of the room. "Could be a test subject. Maybe someone tried to fight the mutation."
"You think the resistance serum is real?"
"It's the only reason this guy's still breathing."
The creature groaned and, for a second, its eyes met Yu Ren's. There was a flicker there—of something human. Something pleading.
"I think it's in pain," Yu Ren whispered.
Kai didn't answer. He walked forward, slow, almost respectful. He crouched beside the creature and spoke softly. "Who did this to you?"
The thing opened its mouth—and let out a garbled, broken sound: "No..."
Then its body convulsed—like a glitching recording. A rattled, metallic shriek burst from its throat as its veins lit up with unnatural, flickering orange. Kai leapt back, just in time.
"RUN!" he shouted.
Yu Ren didn't need to be told twice.
They scrambled down the fire escape as the building behind them exploded in a howl of static and shriek, like a corrupted alarm trying to reboot itself through flesh.
Once they were safe behind an overturned truck, Yu Ren collapsed against the side, panting.
"That thing—what the hell was that?!"
Kai didn't answer right away. His brows were furrowed, lips pressed tight. "The mutation was paused. Which means someone had control over it. Someone injected him with something. Not the system. Something else."
Yu Ren looked at him. "Is this what Project Halo was working on?"
"I don't know," Kai said. But he looked shaken. "But someone's still experimenting. And we just walked into one of their test zones."
Yu Ren leaned back, staring at the sky. His heart was racing.
Then he looked at Kai—really looked at him. "Thanks. For earlier. You pulled me back."
Kai didn't meet his eyes. "Don't mention it."
Yu Ren smirked, even through the exhaustion. "Your smile earlier was dangerous, by the way."
Kai looked at him sideways. "How?"
"Made me think you weren't as cold as you pretend to be."
This time, Kai didn't deny it.
He just walked ahead.
And for once, Yu Ren didn't feel like he was being left behind.
---
"You Think I'd Let You Go Alone?"
The room fell into a heavy, almost sacred silence after Yu Ren's final words. Not because they were shocking, but because they felt... irreversible.
Kai watched him carefully. Then, without a word, Kai turned and crossed the small room, grabbing his satchel and that worn black hoodie he always wore when traveling.
Yu Ren blinked. "What are you doing?"
Kai didn't look at him. "Packing. Obviously."
"You're—what?"
"You're not going alone," Kai said simply, stuffing the medical supplies into the front pocket. "If you think I'm letting you run into another nest, solo, after last time, you're actually insane."
Yu Ren stared. "Kai, I wasn't trying to—"
"You weren't trying to get yourself killed? Really?" Kai snapped the satchel closed and finally looked him in the eye. "Because leaving without telling me is exactly how you get killed."
Yu Ren's jaw tightened, his expression unreadable for a moment. Then, finally, he sat down slowly at the edge of the bed. "I just thought... I didn't want to drag you into another dangerous mess. Especially when we don't know what's down there."
"And you think I care about danger now?" Kai replied, his tone softer this time. "I've already chosen to stay with you. Whether we're scavenging for meds, fighting off another mutant, or dodging the system's weird trials—you don't get to choose for me anymore."
Yu Ren's throat bobbed, words lost somewhere between gratitude and guilt.
Kai continued, quieter now. "You've seen it too. The way the nests are starting to cluster near signals... they're hiding something."
"Or someone's using them," Yu Ren muttered. "Like chess pieces."
A memory sparked in Kai's mind—those whispers from the communicator. "Initiate convergence protocol." The puzzle was growing, and the pieces were slowly falling into place.
Kai exhaled. "What's the plan then?"
Yu Ren tapped his fingers against his thigh. "There's an entrance to the southern tunnel system that goes beneath the old commercial district. The signal came from there. It's probably unstable, and there might be more than just mutants."
"So same as usual," Kai quipped. "Good. I was getting bored."
Yu Ren snorted despite himself. "I hate that I'm starting to believe you actually enjoy this."
"Enjoy is a strong word. Let's say I enjoy not being left behind."
---
[SYSTEM UPDATE]
New Subquest: "Investigate the Southern Signal" Location: Subterranean Ruins (Sector D-13) Danger Level: High Reward: Unknown Skill Data + ???
Quest Sync Option: [Yu Ren + Kai]
Sync Rate: 84%
Tip: Cooperation increases survival rate.
---
By late afternoon, they had crossed the outskirts of the commercial ruins—once bustling plazas now overgrown with vines and collapsed signage. Cars rusted where they'd stopped forever. A mutant rat skittered past them the size of a terrier, but neither flinched.
They found the tunnel entrance hidden beneath a buckled parking structure. The scent of rot was thick in the air, and somewhere deep in the dark, something was breathing.
Kai flicked on a flashlight. "After you."
Yu Ren smirked. "Ever the gentleman."
As they descended into the tunnels, the oppressive darkness swallowed the outside world. Cold concrete walls. Wet mildew. The scent of blood not yet dry.
And then—a whisper.
Both of them froze.
It wasn't system-generated. It wasn't feedback. It was a voice.
"He's waiting."
Yu Ren's breath hitched. "Did you hear that?"
Kai nodded, jaw tight. "Yeah. Who's he?"
Suddenly, the system pulsed again.
---
[NEW THREAT DETECTED]
Mutation Type: Unknown
Signal Disruption: Active
Visibility: Reduced
Threat Level: S-1 (Sentient-Class)
Note: Proximity to Core Signal Source
Warning: Proceed with extreme caution
---
Yu Ren's heart pounded. He looked at Kai, who looked completely unfazed—but his hand was already on the hilt of his blade.
"Kai," Yu Ren said quietly, "If I... if I tell you to run, you run."
Kai didn't even blink. "If you think I'd leave you behind, you still don't know me."
---
To be continued.