Wild West bank robber Dee Bishop (Dean Martin) is captured during a hold up. He is condemned to death and the township summons a professional hangman to carry out the sentence. Meanwhile, Bishop's brother, Mace (James Stewart) hears about his brother's plight and manages to impersonate the hangman. Mace helps Dee and his gang to escape then turns his attention to the bank which they were trying to rob. He succeeds where they failed. As they escape, the brothers take a hostage: Maria Stoner (Raquel Welch) who was widowed in the bank raid. Whilst Mace does his best to convince Dee to give up a life of crime, Sheriff January Johnson (George Kennedy) and his posse chase the brothers and their men across the border into Mexico. This is the home of the Bandolero, the Mexican bandit, a hostile territory for Americans.