When Judy Barker, the Pine Hollow veterinarian, offers Lisa a chance to visit the stables at the racetrack, Lisa jumps at the opportunity. She's been working on her skills as a photographer, and she'd love to take pictures of some of the Thoroughbreds – especially a beautiful mare that's training for the upcoming Preakness race.
Then Lisa, Carole, and Stevie learn that one of the racehorse owners may be using drugs illegally to improve his horse's chances of winning. And one of Lisa's photos may supply the proof of this crime that the authorities are looking for...