Rex the wonder horse's owner is murdered by Joe Regan, the leader of a band of smugglers. RCMP Sgt. Jack Gordon has been sent to capture the villain. Rex vows vengeance on Regan and helps Gordon capture him.

A cowboy and a wild horse find they have some things in common: both have enemies out to get them and both must save their mates from danger.

A stallion known as "The Black" is the leader of a band of wild horses. A cowboy is determined to capture and break him.

Jack Wade is the son of a wealthy father who runs a successful ship-building company. He uses his athletic prowess to defeat the villainous competitors who are out to financially ruin his father.

A boy's family is wiped out in an Indian massacre of a wagon train and he is captured. He befriends a wild colt. Years later, following his escape, he is recaptured by Indians who force him to fight their vicious devil horse . The horse looks somewhat familiar.

A wild stallion (Rex the Wonder Horse) becomes the protector of a prospector and his foster daughter as two thugs plot to steal their claim.

It seems that an evil saloon owner not only wants this valuable steed for himself, but also its owner, the beautiful Mary Ellis. Enter honest gambler Jack Crosby, who wants to settle the score.

A forest ranger comes to the aid of his fiance and her father when a crooked rancher and his gang try to force them off their land.

Human cowboy hero is teamed with Rex, King of Wild Horses, an ornery critter but a magnificent animal.

Jed Campbell, a "skypilot," and Nanette, a dance hall girl, meet when each goes to rescue Rex, "King of the Wild Horses," from a trap.