Canfield, respected rancher, is involved in crooked horse racing, and also leads an outlaw gang! Some 10 years before our story, the gang raided an isolated cabin, leaving 5-year-old Frankie an orphan. The boy grows up wild, his only friends the wild horses...now joined by El Diablo, a savage but very fast race horse that Canfield steals and loses, in the process killing ranger Elliott Norton. Norton`s ranger brother Bob now appears in the region to find his brother`s killer; menaced by the outlaws, the vigilantes, and the Devil Horse, his only chance may be to enlist the aid of the now-speechless Wild Boy.