Felicia and Joan take a summer job at a mountain resort in the Black Hills of South Dakota, caring for a lively group of 6- to 12-year-olds eager to ride horses, camp, swim, and explore. But one girl isn't having fun - she's the saddest child anyone at the resort has ever seen. As Felicia and Joan try to show her love and uncover the source of her pain, they find she doesn't make it easy. Then, during a trail ride, the girl disappears - and Felicia has only moments to decide whether to risk her own life to save her.