In this western, the bad guy kills a rancher and a Texas ranger so that the location of a copper mine will remain a secret. Another ranger goes undercover to catch the outlaw. The killer hires him. His assignment is to create trouble for the late rancher's daughter who has taken over the land. He cons her into to giving him the deed for the ranch. He takes it to the outlaw, but first he stops to warn the other rangers.

Jack has been called in to investigate stage robberies where the stolen gold bullion mysteriously disappears, He finds the Professor, an elderly ex-con, and convincing him they used to work together, gets the Professor to get him in to the gang. Now posing as an outlaw, he learns what the Professor does with the bullion, but he is in trouble when his true identity is revealed.

A cowboy goes after a gang of stagecoach robbers who murdered his brother.

Manuel and Carga are after the hidden map of a gold mine which is somewhere in the hacienda willed to Manuel's brother, Don Careta. Following the third midnight raid on his home, Don Careta is fearful for the safety of his daughter Wanda, and sends for Jack Martin to help him.