Jess Ryder, a detective for the Cattlemen's Association, infiltrates a gang of cattle thieves headed by Mort Snyder of the Snyder Land & Water Co. Snyder's henchmen, including Bat Murchison, have been killing cattle with injections of snake venom to force the Langton family to sell their ranch. Jess takes Murchison captive, but is outwitted by Snyder and loses his prisoner. Langton foreman Jim Fletcher takes Jess to meet Sally, the owner's daughter. They manage to take three of Snyder's men prisoner as they come onto the ranch, but Jess lets two of them go, saying he was sent by Snyder and insisting they take him to Sally's father, who is being held hostage. Once led to the hideout, Jess ties-up Snyder's men and prevents Langton from signing over his ranch. In the meantime, Jim and Bob Langton bring a sheriff's posse to the hideout. Murchison confesses to poisoning the herd so Snyder could buy the ranch, and the entire gang is arrested by the posse, after which Sally and Jess get together.