Jerry Hixon's ranch is being besieged by raiders so Ben sends for his friend Bud. When Bud arrives and finds that the outlaw Texarkana Pete has been captured, he buys Pete's clothes and posing as Pete joins the outlaw gang. But he is quickly in trouble when his masquerade is exposed.
It's time for the stagecoach race to win the mail contract and the only entries are Reden and Farrell. Reden's men kidnap Farrell's daughter and then force him to withdraw. Wally rescues Ruth, buys out Farrel, and enters the race himself. But Reden has his men planted along the course to make sure Wally doesn't win.
Purchasing the Carney Carnival and Road Show, unscrupulous sportsman Martin Trask assumes he has ownership of Rex, the world's greatest trained horse, and its rider, Margie Smith. The girl releases Rex, flees from Trask in a runaway wagon, and finds shelter with young cowboy farmer Jack Merritt, with whom she falls in love.
When Montana cowpuncher Larry Benson, riding his horse Starlight and accompanied by his dog Rex, tied up at the hitching post in front of McAvoy's hotel in Dam, Texas, he had little idea of the extraordinary series of adventures that were in store for him, Starlight and Rex.