The Happ family, Mary (Karen Black, HOUSE OF A 1000 CORPSES, EASY RIDER), and her two kids, Livvy and Jeff live by a quiet lake outside town. Mom works and has to go out of town on business trips, which isn’t normally a problem, until ‘Cousin’ Oliver comes to stay. Oliver has been institutionalised since birth, but after an accident that leaves him in a coma, Mary can’t afford the medical bills, so decides to care for him at home. Soon after he arrives bad things start happening and they find themselves awash in a sea of blood.