It had been weeks since Billie heard another human voice. The streets were empty, overrun by decay and the echo of chaos long gone. Power lines dangled like vines, cars rusted in place, and buildings slumped under the weight of silence. She walked alone now, carrying nothing but a backpack full of scavenged food, a blood-stained baseball bat, and the memories of everyone she lost. Today, she found herself outside a strange facility—an old science lab on the edge of the city. The doors were busted open, and eerie green light spilled from the cracked ceiling panels. Something told her this place had answers.

The infection had evolved, mutated. At first, it was a parasite, small and slick, introduced through water or air—no one really knew. Those infected turned into Thrashers, fast and violent, their muscles stretched and torn from constant movement. Then came Whispers, the ones that creeped Billie out the most—slow, patient, and nearly invisible in the dark. They’d follow you for miles without a sound. Deep in the sewers, people spoke of Veins, bloated creatures with glowing arteries that pulsed like lava. They exploded into acid if touched. Rumors mentioned Sirens, rare and haunting, that mimicked the voices of loved ones to lure people into traps. Billie had seen them all—barely survived them all.

Inside the lab, the air was heavy with chemicals and mildew. Shattered screens flickered static, while charts and test samples lay scattered across the floor. Billie moved carefully, scanning each corner with her flashlight. The deeper she went, the more unnatural it felt—like the lab itself was watching. There were signs of a struggle: claw marks on the walls, a bloody lab coat still draped over a chair, and broken canisters labeled with biohazard warnings. Whatever started this… it started here. And maybe, if she could find out how to stop it, she wouldn’t be the last one left.