When John T. Chance (John Wayne), sheriff of the small western town of Rio Bravo, arrests murderer Joe Burdette (Claude Akins), he knows that Joe's brother Nathan (John Russell) and his gang would do anything to free the prisoner. Whether the sheriff would survive the six days until the marshall arrives is highly uncertain. To avoid further victims, Chance wouldn't even let the people of Rio Bravo help him. So it's a good thing the sheriff has his friends alcoholic Dude (Dean Martin), hotshot Colorado (Ricky Nelson) and deputy Stumpy (Walter Brennan) to stand by his side in this seemingly hopeless situation.