Ernest Shelby, New York man-about-town, arrives in Winston, Arizona, to claim his late uncle's estate - a big cattle ranch named Red Rock. He intends to sell the property and return east but when he discovers, before going to the ranch, that more than half of Red Rock's 10,000 head of cattle has disappeared mysteriously, so he stays on to investigate. His suspicions center on Sam Hepburn, a local big-shot who operated the ranch for Shelby's uncle. Hepburn's spoiled and imperious daughter, Anne, goes to Winston to collect the ranch payroll and is held up on the way back. But Shelby rescues her and chases off the bandits. Anne accuses him of staging the hold-up to impress her. Dave Hyslip, Hepburn's foreman, is resentful of any any attentions paid to Anne. When Ernest arrives at the ranch, he is mistaken as a cowhand looking for a job and Hyslip, unaware of his identity at the time, hires him. Later, Hyslip, responsible for the rustling, places a rattlesnake in Ernest's bunk, but he is saved by Nebraskee. Ernest and Nebraskee locate a secret canyon, and an incident they observe convince him that Anne's father is indeed behind the rustling. He isn't but it appears that Hyslip will get away free until George learns the reason for Hepburn's mysterious activities.