Roy Rogers, a Nevada State Ranger Captain in charge of the Rangers Reclamation Service, makes a trip to Las Vegas for the annual Heldorado Frontier Days Festival, as he wants to help his old friend Gabby Whittaker who originated the idea (at least, in this film).In Las Vegas, Roy meets heiress Carol Randall, who has been selected as the Queen of the Heldorado. Roy is informed that the F.B.I. wants an immediate investigation of the counterfeit thousand dollar bills that are being passed over the gambling tables at the casino.

A ranch owner turns his place into a home for boys who have lost their fathers in World War II. His evil female lawyer covets the ranch and uses a gang of local toughs, a pack of killer dogs, and a phoney rancher's beneficiary to get it. U.S. Marshal Rogers opens an investigation when the rancher is killed.

Anchor is building a railroad and to get cheap labor he gets Black Hawk's Indians to attack and burn the incoming wagon train. This forces the settlers to work for Anchor and he pays them in devalued scrip. When Rex figures out Anchor's swindle, Anchor gets Black Hawk to capture him. When Anchor turns on Black Hawk and shoots him, Black Hawk gets a chance to repay a debt to Rex.

Gridley is mining silver from an old Mexican mine and bringing it into the USA thru a passage into his worthless mine. Border guard Rogers suspects Gridley and finally finds the secret entrance to the Mexican mine. He sends Lee Madison for help only to have her captured by Gridley. Trigger brings help that takes care of Gridley's men and now Roy has to rescue Madison.

A cowboy turns bounty hunter to pay off his debts.