At Slim Phillips' carnival, Gabby Whittaker and circus owner Sue Farnum meet Slim, who is Sue's late father's old partner, and ask him for help. A man named Ripley is claiming that Sue's father owed him money and if she does not repay the debt, he will sell the circus and her California ranch. Slim remembers that Farnum paid the debt and he and his daughter Patty, who is enamored of the California movie culture, accompany Sue and Gabby back to the ranch to find the receipt for the payment. On the way home from the train, gun-wielding bandits and cowboys roar past their car, and Patty is thrilled to learn that they have stumbled onto a Roy Rogers movie set. Roy, finding Sue attractive, apologizes and invites them to a barbecue that night. At the barbecue, some men kidnap Slim and disable the actors' cars, so Roy tries to follow on his horse, Trigger, but cannot catch them. Later, when Sheriff Tom arrives and Sue tells him that she suspects Ripley, they find Gabby in the closet, tied up but unharmed. Roy is about to leave until the children who live on the ranch tell him that Sue's business is in jeopardy. Although Roy's friend Bob tells the children that Roy is only a hero in the movies, Roy agrees to stay and help. He suggests to Sue that they put on a circus to make enough money to repay Ripley, and when she says that they need big attractions for that, Roy agrees to supply the spectacle. The next day, the whole film cast and crew parades through town with a sign proclaiming that Republic's western stars Roy Rogers, Wild Bill Elliott, Allan Lane, Donald Barry, Robert Livingston and Sunset Carson will be at the show for one night only. Later that day, Ripley and his henchman Maxwell break into the ranch looking for the receipt. When Roy, Gabby and Bob see them and realize they are up to no good, Roy distracts them while Gabby tricks Bob into letting him climb into the trunk of their car in order to eavesdrop. Miles away, the men park and the car rolls down a hill with Gabby still in the trunk. He escapes unhurt but does not hear any of Ripley's plans. Back home, Gabby remembers rolling down a hill and surmises he must have been at the old dry wash, so Roy, Gabby and Bob go there to pick up the car's trail. They find tracks and, following a skunk scent Gabby recalls, arrive at an abandoned mine shaft, where they are promptly shot at by Ripley's men, who are guarding Slim. Roy, not wanting to shoot inside for fear of harming Slim, fires his gun at the chimney, causing the shack to fill with smoke. The men are then forced to surrender but do not reveal Ripley's involvement. Meanwhile, Maxwell tells Ripley that he overheard Slim tell Sue the receipt is in the bank. When the circus begins, Ripley and his men steal the receipt and run away. Roy and the rest of the Republic heroes then leave the circus and chase after Ripley's men, and after all are captured, Roy finds the stolen receipt in Ripley's jacket. The stars then turn the men over to the sheriff and return to the circus for the big finale.