Outlaws attempt to drive Colonel Lee (Charles Clary) off his ranch to prevent him from entering horses in the cross-country races. Martin Brierson (James Farley), the outlaw leader, tries to buy Lee's ranch but he refuses to sell. Farley's brother Pete (Paul Hurst) sets fire to Lee's barn, injuring his horses. Ranch foreman "Lucky" Larkin Ken Maynard) suspects Brierson as the man behind Lee's trouble and he decides to ride Lee's pet colt Tarzan (Tarzan) in the big race. Brierson makes an unsuccessful attempt to have Tarzan disqualified, but Larkin rides Tarzan to victory. He than captures Pete and forces a confession out of him and both Brierson brothers are arrested. Larkin then marries Emmy Lou Parkinson (Nora Lane), a homesteader's daughter.