dRoy Rogers, engineer on a new state highway, has just warned men at the nearby youth rehabilitation work camp of an impending explosion when a herd of cattle stampedes into the blast site. Roy hurriedly drives them away, but despite his efforts, several of the cattle, belonging to rancher Andrew Willard, are killed in the ensuing landslide. Willard strongly opposes the highway, which will cut across his ranch, and unknown to Roy, Devery, Willard's top hand, purposely drove the cattle into danger. Roy heads for the Willard ranch to offer payment for the dead cattle, and encounters Willard's niece, June, who advises him to avoid her uncle's wrath. Roy offers payment, but a furious Willard insists that his cattle are all expensive, prize livestock. When Roy disagrees, charging that the dead animals were scrub cattle, Devery throws him out. Although the state has paid for Willard's land, Willard refuses to cash the check. Devery now suggests that they create an epidemic of crime to force the prison board to shut down the camp, which will effectively end the highway project by eliminating the work force. When Willard refuses to condone robbery and murder, Devery reminds him that he had certain records altered to cover the fact that he stole 5,000 acres of ranch land. Realizing that he would go to prison if the doctored records were discovered, Willard agrees to Devery's plan. Devery reveals that he has planted his own men as cook and handyman at Splinters McGonicle's Guest Ranch, where Roy is staying. That night, Devery's men break into the cabin of Splinters' guest, Mrs. Edsel, and steal her diamond pin. She immediately accuses Jim Corley, an inmate of the prison camp, whom she saw around the ranch earlier in the day. Although Warden Parker defends Corley, the sheriff arrests him, and Corley escapes in Mrs. Edsel's car, successfully evading Roy's pursuit. Meanwhile, Willard continues his attacks against the highway, but the warden maintains that the road camp helps to keep first offenders from the bad effects of prison. That night, the warden catches Devery's men in the act of stealing dynamite from the camp and is killed. They set an explosion to cover the crime, but upon examining the site, Roy concludes it was not an accident. Greatly upset by the death of their mentor, the men at the prison camp vow revenge, but Roy, tipped off by Splinters, is able to convince them that the best policy is to abide by the warden's ideals. In the morning, June spots Corley when he tries to steal some food from the Willard Ranch. He begs her to allow him to speak with Roy, and she searches Roy out at a rodeo at Splinters' ranch, which is being attended by the prison camp inmates. Before she can tell Roy that Corley is waiting nearby, the sheriff reports that evidence found after a bank robbery indicates that someone from the camp was involved. After the sheriff takes charge of the inmates, Corley shows Roy that Devery is stealing Willard's prize cattle and replacing them with scrub cattle. Devery notices them and chases them to Willard's ranch. Willard is gone when Roy arrives, but he tells June what he suspects. Devery then explains that Willard has approved the exchange, but Willard arrives unexpectedly, having examined his cattle, and verifies Roy's story. After Devery admits his theft, Willard threatens him with jail and draws his gun. Devery kills Willard, and while Roy fights Devery and Corley holds off the cowhands, June rides for the sheriff. Finally, Roy escapes, and he and the wounded Corley head for Splinters' dude ranch. When the sheriff and his deputies arrive, Devery's men hold the ranch guests hostage, but with the help of the men from the prison camp, Roy overcomes Devery. After Devery is arrested for murder and rustling, the sheriff announces that he has changed his mind about the road camp and wants it to continue with him as the new warden.
