Undisputed (2002)

Monroe Hutchen was once a promising heavyweight contender until he was convicted of murder and sentenced to life without parole at the Sweetwater maximum security prison in California. Now, Hutchen boxes behind bars, and he's become the champion of a loosely organized prison fighting circuit. When heavyweight champion James 'Iceman' Chambers enters Sweetwater after being convicted of rape, Hutchens finds the serious competitor in the same lockup for the first time, though Chambers scoffs at the jailhouse champ. When heavyweight champion James 'Iceman' Chambers lands in prison, the resident gangster arranges a boxing match with the reigning prison champ.