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.

"THUNDER OVER THE SOUTHWEST!"