Summer detention for four outcast teenagers means being assigned to clean their high school after a heinous incident. But they are not alone; a macabre gang dressed as The Four Horsemen Of The Apocalypse - Famine, Pestilence, War, and Death - has locked them inside and is hunting them through the school's ravaged hallways. As the four students fight for survival, they must confront the supernatural echoes of past traumas they have struggled to forget - and may be condemned to relive.