An old prospector discovers a bonanza mine of gold on the Diamond Dude Ranch. He tells two men about it and they kill him, and then make plans to acquire the ranch. The property is owned by an easterner named Bob Jordan and is operated for him by John Grant, but it quickly becomes the scene o many mysterious mishaps and the few remaining guests are planning to leave when Jordon arrives. Dr. Pike and Mr. Cooper make an offer to buy the ranch but Joan Grant, the foreman's daughter, tells Bob the ranch can be made to be profitable if he would make some improvements. Bob spends most of his money on the construction of a dam, to improve the water supply, and then hires "Broncho" Wilson, the World's Champion Rider, and his Wild West Rodeo troupe, including Vera McGinnis, the World's Champion Trick Rider, to stage weekly shows. The remaining guests stay on, and many others show up. Among them are Joe Jenkins and his mother who chose the range to quiet her jaded nerves. Joe accidentally overhears Pike and Cooper, the men who killed the prospector, talking about their plan to dynamite the water supply, but they kill him before he can tell anybody and then plant evidence indicating that John Grant was the killer. Later, after Jordan rides after Pike to take him a briefcase he had left at the ranch, he trails Pike and Cooper to the hidden mine. The villains, after cutting the telephone wires, send their henchmen to attack Jordan and Joan at the ranch.