When frazzled high school teacher and Army veteran Don Keller (Steve McDougall) can't deal with the pressures of his job, he has a psychotic breakdown and turns into a self-possessed killer. Armed with his military training and a serious case of the crazies, he takes over the school and turns it into a horrific nightmare. Can a group of students serving detention join forces to bring this bloody rampage to an end -- or will they die trying?