Kirstie Scott lives at Half-Moon Ranch, where her mother runs a pony trekking centre. She has her own palomino pony and together they love riding the local trails. Storms, floods and earth tremors are all facts of life in this wild terrain, and at times the landscape itself proves the enemy to the horses and riders. Kirstie and her palomino, Lucky, are as close as a horse and rider can be. But now a mystery illness threatens their partnership and puts Lucky's life in danger. Neither the local vet, not Kirstie's brother, Matt, can identify what's wrong. So Kirstie makes a third and final attempt to find a cure for her horse. Driving Lucky deep into the Rockies, she seeks out Zak Stone, a reclusive but legendary horse doctor - will he be able to save Lucky's life?