James Animal Allen (Ving Rhames) is serving a life sentence for murder at Folsom Prision, having taken the fall for his eldest son. The inside world of the prison is a brutal hierarchy based on power and influence, often divided by race. When a riot breaks out between the Blacks and the Mexicans, Animal is transferred to his old stomping ground, Susanville. While serving his time, Animal learns that his son, James Jr, is framed for murder, with the person responsible for the frame-up calling the shots from the inside. But when James learns that he can free himself and possibly save his son, he finds that he can only do so if he returns to his dark past as a cage-fighter, and allow himself to be blackmailed by the syndicate operator - the same guy who's framing James. Once Animal learns that his next fight is to be against Uno - his former Hispanic rival in Folsom prison - he realises that Kasada, the ringleader, has been orchestrating a race war and the ultimate downfall of both gangs all along.