On their way to Rimrock, Bob Banning and Chito Rafferty aid an elderly prospector, Ben Jason, whose wagon has broken down. He gives them a nugget and asks them to meet his niece, Judy, in Rimrock and tell her he is on the way. They do so and then sell the nugget to Matt Wyatt, the local assayer. The latter recognizes the nugget as having come from the famous "Lost Dutchman" mine, and decides that Jason must have re-discovered the mine. He schemes with gambler Anse Morgan and his henchman, Rocky, to ambush Jason. They do so, murder the old man and take his map. Bob and Chito arrive to late to help Jason but in time to make the sheriff think they are the culprits who did the killing. Judy thinks so also. They have to find a way to clear themselves but they first must get out of jail.
—Les Adams <longhorn1939@suddenlink.net>