Sarah is an autistic little girl whose father is worried about her health. Concerned for her, the father sees a removal from the hospital by force as the only option. An elevator break-down prevents a smooth exit and renders them trapped with others. Yet the incident is only the beginning of a descent into nightmare. As the doors open, the hospital appears mysteriously deserted. When mutilated bodies are found, creatures from a dark world start a frightening attack. It soon becomes clear that the survival of the group may rest solely on the little girl.