[1] Drifter Johnny Moon (William Shatner) is frequently attacked as he is mistaken for his twin brother Notah who leads Comanche war parties in attacks on the white population whilst he is having visions on peyote.

Johnny travels to a Comanche encampment where he challenges his brother to a fight to the death in the town of Rio Hondo.

When Johnny rides into Rio Hondo he finds the town is at boiling point between two warring factions with only Sheriff Logan (Joseph Cotten) keeping the peace.

William Shatner travelled to Spain In March 1967 during a break from his shooting schedule for the Star Trek television show.

[2] Producer Sam White recalled that Shatner tried to get the NBC network to buy the film to show on television.