After Ruby, the owner of a neighboring lodge, gets sick, Meg and Thomas decide to help her and watch after her ten-year-old son, Tyler, who releases ranch horses that Thomas gets lost trying to find.
Unhappy vacation-mates Becky, Meg, and Alison are distracted from their bickering by a phantom horse and soon find themselves forced to pull together when a friend gets trapped in an abandoned mine shaft.
Becky enters her first endurance challenge, a fifty-mile race over difficult mountain trails, confident in her friend Rob's help, but jealousy threatens her chances when Rob is distracted by a willowy blonde--and soon she realizes some of the riders will stop at nothing to win.
Young horse lover Meg O'Donnell can hardly wait to start her summer at Mustang Mountain, but a sudden storm on the way there leaves her, two other girls, and their driver struggling to survive the elements.
Meg, Alison, and Becky, alone at Mustang Mountain Ranch after Becky's mother is hospitalized, put themselves in serious danger when they attempt to rescue two missing horses in the midst of a forest fire.
Despite the amazing fossils unearthed by 20th-century paleontologists Barnum Brown and the Sternberg family, they waged a bitter rivalry over their finds.
