After his assistant, Bud Lester, is killed, Texas Ranger Speedy Meade bids farewell to his girl friend, convent student Mary Dillman, and sets out to break up a gang of cattle thieves operating on the border. After arriving at the scene, Speedy dons different disguises, including that of a derelict bartender and an old man selling stolen cattle. Speedy obtains valuable information and learns that the leader of the band is Henry Dillman, Mary's father. Mary arrives and complicates Speedy's plans. He trails the gang to their secret rendezvous, but Mary causes him to lose his advantage and he is captured, bound, and gagged. Dillman is accused by the others in the gang of having betrayed them to the ranger. A fight ensues in which Dillman is shot and Mary is seized by a bandit. Speedy frees himself and knocks out Mary's assailant. Dillman confesses he is not really Mary's father, and Mary goes off with Speedy.