Darby is a lucky girl. After years of dreaming about horses, she is finally surrounded by them on her grandfather's ranch in Hawaii. To top it off, she even has a horse of her own — Hoku, a wild mustang she helped rescue. After a few months together their bond has never been stronger.

But when Hoku must be set loose among other horses, her untamed spirit returns. As Darby tries to reestablish their relationship, even worse news arrives: Hoku's original abusive owner, Shan Stonerow, wants her back. Without a deed of ownership, could Darby lose the horse she loves?