Lisa Atward's first day at Pine Hollow Stables is a disaster. When snobby Veronica di Angelo befriends her, Stevie Lake thinks Lisa is just another spoiled little rich girl. Carole Hanson has to agree. Then Lisa's cell phone rings in the middle of a lesson and spooks Stevie's horse. Stevie is furious. But when Lisa ruins Veronica's plan to scare Stevie Lake's hors while they're on a trail ride, Stevie and Carole Hanson decide she is best friend material after all and persuade Max to allow her to go on the Mountain Trail Overnight.
On the Mountain Trail Overnight, Veronica develops a crush on Phil Marsten, but to her dismay, he only has eyes for her rival, Stevie. In an attempt to her get Phil's attention, Veronica endangers herself and her horse and winds up alone and unconscious in the woods.
When Veronica's horse, Cobalt, returns to camp riderless, Carole, Stevie and Lisa, together with Phil, put themselves in danger from wild dogs to rescue Veronica.
After this adventure, the three girls form the Saddle Club - vowing to be loyal friends and remain horse crazy forever!