Al Parker, an aviator and Secret Service agent, is assigned to investigate a gang of bandits who have been robbing a platinum mine on the Mexican-American border. The superintendent of the mine, John Ames, is killed when he discovers a secret passage used by the bandits, and his daughter, Edith, assumes the running of the mine. Edith is kidnapped by the gang's leader, McLeod, who makes his escape in a waiting airplane.