Fourteen-year-old Grace MacLean and her friend Judith go horseback riding in New York on a winter morning, but their horses lose their footing and slide onto a road, where Judith and her horse are killed by a jackknifing truck. Grace has her right leg amputated, and the incident causes a lasting trauma not only to Grace but also to her horse, Pilgrim. Grace's mother feels there's a link between her crippled, embittered daughter and Pilgrim's behavior....