Becky Sanderson enters her first endurance challenge, the Wildflower 50. She and her mother's chestnut mare, Windy, must race 50 grueling miles over rough, steep mountain trails. Becky is confident she can do it, especially with the help of her friend, Rob. But Rob unexpectedly gets distracted by another racer, a willowy blonde whose behavior is more than a little suspicious.

Will Becky's jealousy get in the way of finishing the race? The competition gets tougher, and for some of the riders it seems there's more at stake than first place. Becky is caught up in a vicious race with riders who will stop at nothing to win.