After a car accident in the mountains of Montana, six friends - Jay-Jay, her brother Josh, Bug, Holly, Peter and Karen - decide to find a shelter to protect themselves against the cold night. With the exception of Karen, the other five friends break in a facility using a rope through the skylight, but the rope breaks and they become trapped in the laboratory. They find two scientists dead and another completely insane, and they realize that the team of scientists was conducting experiments with a serial-killer in coma. When each youngster sleeps, the Sleeper invades the dream turning his victim into a slayer. The survivors try to escape from the sleepwalkers and find an exit.