Riley's reunion with her estranged sister Tina was already going to be difficult — years of distance, unresolved conflict, and a relationship that ended badly. Walking toward Tina's new home through dark, rain-soaked alleyways, she realizes she is being followed. Two masked men with wrong-looking movements close in. She barely makes it inside before they break in behind her, and then everything goes dark. She wakes alone in a cold, sterile underground bunker. Tina is gone. Distorted voices echo through the corridors. The people who took them have been mutated into something that barely passes for human. She meets Charlie — a clever, tech-capable survivor who has been trapped here longer than she has — and together they push deeper into the facility, uncovering the experiments that produced everything around them. Tina is alive. The reunion is brief. A full outbreak erupts before they can do anything with it, and they run into the night, into a vast, fog-thick cornfield. A red light pulses somewhere ahead. They move toward it. The bunker was only the beginning.