Bull, the leader of a gang, disguises his men as Indians and leads them in an attack against a wealthy wagon train. A young boy, Buzzy, sneaks away, and summons the rangers. The arrival of the rangers disperses Bull's gang. Buzzy introduces his older sister, Alice, to Bob, a ranger, who has become his idol. Bob collects evidence that contradicts the claim of an Indian attack, and he goes undercover as a prospector. When Bob goes to the saloon in Hopi, he meets Bull and some of his men. Bob notices that the tassels on Bull's outfit match one that he found at the scene of the wagon train attack. After Bull challenges Bob to a fistfight, which Bob wins, Bull's gang captures Bob. Bull takes Bob's ranger badge, and sends it with a message to the other rangers. The message, presumably from Bob, diverts the rangers from escorting an incoming wagon train, which Bull and his men, dressed as Indians, plan to attack. Bob's horse, Pal, helps Bob escape his ropes and he prevents the train from entering a mountain pass that the outlaws have planted with dynamite. Instead, Bull and his gang are caught in their own explosion, and Bob holds Alice in his arms.