Ken Maynard's exceptionally intelligent horse, Tarzan the Wonder Horse, is the star of this western about evil cowboy Steve Frazer (Welch) who gathers horses for slaughter, whose meat is sold to pet food manufacturers. The wild horse Tarzan frees the doomed horses from their corrals, and Frazer convinces the Sheriff that Tarzan is a threat and can be shot on sight. Local cowboy Ken Benson (Maynard) and rancher Pat Riley (Kennedy) work together to clear Tarzan's good name and put Frazier behind bars for his evil deeds..