Arizona Ranger Larry Grant is posing as an outlaw while hunting for an outlaw gang, secretly led by Lance Corbin, that is stealing silver in Mexico and smelting it into bars for sale in the United States. Sheriff J. Quincey Jones arrests Larry, who is broken out of jail by two of the outlaws, while fellow Rangers George Barnes and Bill Harns follow them to the entrance of the gang's mountain hideout. The gang kidnaps Dolores Alvarez, the daughter of a rich Mexican mine owner, and holds her for ransom. Larry helps her escape and leaves her in safety with Patricia Jones, the sheriff's granddaughter, and then he, Barnes, Harns and Jones ride to the hideout stronghold for a showdown with the bandits.