Just after the American Civil War, a former soldier, Hogan, rides up on a naked woman about to be raped by bandits. Hogan kills the bandits, showing not only that he can shoot, but that he is an expert with explosives. He is taken aback when he sees that the woman he has saved is a nun. Sister Sara is raising money to assist Mexican revolutionaries who are fighting the French. When Sara requests that Hogan take her to a Mexican camp, he agrees because he had previously arranged to help the Mexican revolutionaries attack the French garrison in exchange for half the garrison's treasury, if they are successful.