To save her ranch after the accidental death of her husband, Sarah Fellows (Marilyn Lightstone) marries Frank Chase, the man responsible for the mishap. She and her children move into Frank’s house, but Sarah makes it clear that it is only a “marriage of convenience”. Deeply resenting the situation, her twelve-year-old son Christopher becomes withdrawn and increasingly obsessed with a renegade black pony that runs unfettered through the valley. Frank realizes that Christopher needs the pony and buys it for him, despite Sarah’s strong objections. Surprisingly, it is through Christopher’s adventure-filled relationship with this pony that the family discovers the true meaning of devotion.