A fire in the mountains drive a wolf pack into the nearby desert where they terrorize the local residents. The leader of the wolf pack is Lobo, actually a halfbreed (Rin Tin Tin). When the pack is discovered hunting a herd of cows, a posse gives chase. Lobo leaves his pack to lead the posse away. He is injured and found by a local prospector, Dave Weston (Charles Farrell). The prospector nurses Lobo back to health and the two become close friends. Meanwhile, Weston has made a Borax find in the area. His girl friend May Barstowe (June Marlowe), daughter of a wealthy rancher, is pleased. However the local chemist, Borax Horton (Pat Hartigan), actually a claim jumper, plans to steal the claim.
In an early scene where the wolves are chasing the cart of horses, one of the wolves is shot then attacked by the rest of the pack. All other wolves/dogs survive the entirety of the film.