Chris (George Kennedy) is the lone survivor of the original seven gunmen who is recruited to help in a peasant struggle in Mexico. Colonel Diego (Michael Ansara)is the ruthless military commandant of a Mexican prison holding the leader of the revolt. With knife expert Levi Morgon (James Whitmore) and firearms experts Keno (Monte Markham), P.J. (Scott Thomas) and Slater (Joe Don Baker), they enlist the help of the giant black man Cassie (Bernie Casey) and two others to rescue the leader of the proposed revolt. The evil Diego employs his torturous and inhuman practices on both sides of the prison walls in a effort to stop the heroes from rescuing the prisoner in this action packed western saga.