In the 1870s, two rival businessmen, Zack Thomas (Frank Sinatra) and Joe Jarrett (Dean Martin), on a stagecoach heading to Galveston, Texas, must pull together to protect $100,000 from an outlaw named Matson (Charles Bronson). Once in Galveston, however, their rivalry continues, as Thomas joins up with Elya Carlson (Anita Ekberg) and Jarret with Maxine Richter (Ursula Andress). But Matson is still on the loose, and a scheming banker threatens both Thomas and Jarrett.