Jim Bales blames the Garnett outlaws for the disappearance of his brother Hector, a federal officer. But when he wounds Charlie Garnett, his errant cousin, he finds he's no nearer the truth, the wound having caused amnesia. However, sided by Charlie, Jim repeatedly clashes with the gang. They're forced to cross the Rio Grande to Mexico, where they learn what really happened. Then, facing the final lethal clash, Charlie - his mind restored - must decide between his outlaw partners and Jim ...