Sunset Carson and Wes Caven, once boyhood friends, are now deadly enemies: Sunset has become a law-abiding rancher, Wes a hired gun doing the dirty work of the crooked Elwood brothers.
Carson is an eyewitness when a young rancher, Bruce Lanning, kills the murderous Frank Elwood in self-defense. After Wes tampers with the evidence, Bruce is arrested for murder and faces the hangman's noose. Sunset must prove Lanning's innocence, but to do so he's forced to face Wes Caven with blazing pistols.
One of the 1940s' top Western stars, Carson was approaching the "sunset" of his career by decade's end, but he's still in good form in the Texas-made Rio Grande. Black clad, lightning-fast with his shooting irons, and laid back in the face of danger, he's even unfazed while he and the wounded Bruce are trapped in a jailhouse. In fact, Carson casually performs surgery on Bruce while ducking and dodging the bullets whizzing around them!