Arizona Roundup

Mike O'Day's business of herding and selling wild horses is seriously compromised by horse rustlers who are working with Ed Spincer, president of the local railroad company. When Mike sends his daughter Tony to hire two new ranch hands, she holds a contest in which the first two men who reach the ranch by horseback win the job. Tom Kenyon, a government agent working undercover, and Hank Waters, who is working for Spincer as a spy, win the jobs, and Tom convinces Mike to hire his sidekick, Pierre La Fair, as a dishwasher. Shortly thereafter Hank is fired for searching through Tom's saddlebags. Spincer meets with his cohorts, ranchers Duke Carlton and Ted Greenway, whose ranches have the only exits from the valley besides the railroad. They plot to charge such high prices for use of the water on their land and for the railroad that neighboring ranchers like Mike will be forced out of business. Mike and the other ranchers are outraged by this tactic but have no alternatives. One afternoon Tom and Sugar, Mike's youngest daughter, are ambushed while they are out riding. Tom rescues Sugar and they return to the ranch, where Tom reveals his true identity and proposes that as a government representative, he buy the ranchers' herds. As Tom explains that Greenway's contract mandates that any government-owned stock has free water privileges, and that the government plans to build a new railroad through the valley, Greenway eavesdrops on the conversation and wavers in his loyalty to Spincer. Later, Carlton takes Tom and Greenway hostage as the ranchers confront Spincer and his cohorts in town. Tom overwhelms his captors and escapes, then joins the gunfight between Spincer and the ranchers. After Spincer shoots Greenway in the back, he and Tom confront each other. Tom shoots Spincer and the ranchers win back their rights.