Striking outdoor locations highlight Frank Gruber"s story, which details the founding of the Pony Express and how it prevented California from becoming an independent republic. Ruthless killers (Henry Brandon, Stuart Randall) trying to incite a rebellion against the United States, employ devious schemes to prevent Buffalo Bill Cody (Charlton Heston) and Wild Bill Hickok (Forrest Tucker) from getting the Pony Express started. Rhonda Fleming and Michael Moore play siblings who are loyal Californians, violently opposed to the Pony Express and statehood. Directed by Jerry Hopper (The Secret of the Incas).