Cheyenne Hart, a teenage girl, lives a near perfect life on a horse ranch in the mountains of Montana with her parents and grandparents. But when tragedy strikes the family, Cheyenne blames herself and disappears into a dark depression seemingly never to return. Mountain Sky is a heartwarming tale of a girl who perseveres and overcomes tragedy with the help and support of her friends, family and the spirit of a wild mustang who teaches her more about herself than she could ever imagine.