Ring Hassard (Audie Murphy) and his father Jeff (Dean Jagger) live in a hidden valley in the mountains where they capture and tame wild horses. When Ring comes to the rescue of Riley Martin (Wanda Hendrix), a woman lawyer who has lost her way on the trail, it leads to a romance between them but also opens an investigation into Jeff's shadowy past and accusations of murder.
The Hassards encounter more trouble when a gang of horse thieves led by Big Matt Rango (Richard Rober) steal from them and then plot to kill them before justice is served. Wanda Hendrix, who was married to Audie Murphy at the time, makes a fetching heroine and
Sierra is notable fore an early appearance by Tony Curtis in a villainous role and a colorful performance by Burl Ives who performs several Western ballads including "Drift Along" and "Hideaway."