Isolated in the wilderness, Ann (Lucy Walters) struggles to survive after a mysterious epidemic decimates society. Ann's solitary and regimented life is haunted by memories of her past and threatened by bloodthirsty zombies, known as "the infected," that lurk just outside of the forest border. On a desperate journey to forage for food, Ann meets a teenage girl and her injured stepfather. Initially reluctant to let others into her world, Ann relents for both physical and emotional survival. As the infected close in and the trio is forced to fight for their lives, Ann must face the painful truth that these survivors may be more dangerous than the infected.