A viral pandemic causes people to become violent and bestial. Twenty-five years later, young adult Anna and her brother, David, scavenge through the ruins of a nearby city. Spooked by the arrival of a ragged survivor, they flee back into the woods. David injures his ankle and urges Anna to leave him behind, believing their sick mother needs protection. Anna lies to her mother, assuring her that David will return shortly from a hunting trip. When Anna wakes the next morning, her mother is dead.