Michael "Duffy" Duffield, a homeless veteran, drifts from place to place until he meets the talkative ex-convict Max Bomer. After recognizing Duffy's fighting skills during a bar brawl, Bomer offers him a well-paying job. Duffy agrees and realizes that the "job" involves fighting in underground fight clubs. The two make a lot of money from their first fight and decide to travel to L.A. so that Duffy can atone for his past and Max can get even with a gangster boss, Sage Parker. They stay with Rachel, Max's sister, and she and Duffy quickly grow closer. Duffy fights in Sage's Fight Club and wins, which draws unwanted attention to him. Duffy is drawn into the world of crime and is offered several jobs he can't refuse. Among them is one involving Sage's partner, police officer Ellen Ridgway. The deeper he delves into this world, the deadlier it becomes.