A serial killer escapes from a mental institution to frame his brother for murder. Jack 'Maxie' Prime builds a floundering drug business while dodging the police. His dealers are ripping him off for speed. He sees his ex-wife with a new man, abducts the terrified woman and then accidentally kills her. A chain of events kicks off a murder spree after he dumps her body. Jack robs a store but its owner assaults him with a tire iron. He kills the man in self defense then kidnaps a drunken waitress. Jack murders a cop while trying to get rid of her body. Circumstantial evidence gets him busted and jailed for both deaths. District Attorney Dan Foley is assigned to the serial killer's case and demands the death penalty. Jack is committed to a state mental hospital but escapes hell-bent on revenge and soon frames the D.A. for murder. Jack is Dan's long lost brother missing since childhood after the state split the family up because of an abusive father. Down On Jack is like FRACTURE and NATURAL BORN KILLERS.