Bucko, a close friend of Festus, is accused of murdering a man to whom he lost at poker. When his alibi witness lies out of fear, Bucko is sentenced to hang, and Festus, who'd begun to see the marshal as a friend, vows Bucko won't swing. 

Festus's beautiful young cousin, whom he has not seen since she was a little one, arrives in Dodge to keep the pact her father made for her when she was a baby: to marry Festus.