Un equipo de cine va a rodar una película a la misteriosa isla de Teschio, al este de Sumatra. Allí descubren la existencia de una civilización prehistórica y de una tribu ancestral que secuestra a la atractiva Ann, la actriz protagonista, para ofrecerla en sacrificio ritual a King, un gigantesco gorila.
Hearing his brother the Express Clerk is in trouble, Bob Williams rides to the Express Office only to find the safe open, his brother and the money missing, and himself accused of the robbery. To clear himself he trails and finds the outlaws engaging them in a fight. But during the melee, the gang leader double-crosses his men and sneaks away with the money and Bob now has to catch him.
Against explicit orders, a vainglorious cavalry major insists on counterattacking a gang of hostile Sioux Indians. His captain refuses to comply and is arrested for insubordination and cowardice.
Ranch hand Tex Gardy comes to the aid of the father of the girl he loves, whose ranch is being threatened by a gang of criminals led by a woman known as The Hellion.
