Filmed on location in Utah, The Outlaw Stallion top-bills Phil Carey and Dorothy Patrick, but the star of the proceedings is young Billy Gray. Living on a ranch with his widowed mother (Patrick), Billy makes friends with the white stallion who leads the herd of wild horses living under the ranch's protection. Villain Roy Roberts intends to flout the law by corralling the stallion's herd, then shipping the horses across the border. To accomplish this, Roberts uses a fierce black stallion to lead the herd astray. After a hoof-to-hoof fight between the "good" and "bad" stallions, Roberts resorts to kidnapping Gray and his mother to bring the white horse out in the open--and that's where hero Carey justifies his presence in the film.