Wild Hearts Can't Be Broken

Sonora Webster lives with her sister and abusive aunt during the Great Depression. She learns that because of her accidentally letting the cows loose and her suspension from school, her treasured horse Lightning has been sold and she will be placed in an orphanage. Instead, Sonora slips out of the house during the night. She ends up at a county fair and sees a performance by Marie, a diving girl who rides a horse off a platform, and aspires to do the same. Doc Carver, Marie's employer, tells her she is too young but gives Sonora a job as a stable hand due to her ability with horses, and she begins traveling with them. Doc's son Al wins a wild horse in a card game and Sonora names him Lightning. She later surprises Doc by taming and riding Lightning, so he promises to train her as a diving girl if she can mount it while it's moving, which she succeeds after multiple attempts.