Five adolescents desperately seek shelter in a basement, blocking the entrance to protect themselves from a deranged murderer lurking above. The reason behind the killer’s pursuit remains a mystery, leaving the teens to wonder why they have become targets. With the murderer stationed at the basement door, they quickly understand that their escape route is the same path they used to enter. As the situation progresses, they begin to question their own mental stability, and their perception of reality starts to blur.