Trina Ryan's challenging summer starts off with a puppy-fueled energy burst as she takes on another service dog for training--an eight-week-old black Labrador named Colton. And to help explore another dream, she's taken a job at the barn next door in exchange for riding lessons with the barn's schooling horse. Before long, Trina butts heads with Morgan Hart, an ill-tempered but skilled rider with a gorgeous thoroughbred named Knight.

Adding to the list of frustrations is the difficulty in maintaining a long-distance relationship with Chase, her first boyfriend from last summer, while trying to deal with unwanted attention from a new boy in her puppy training class. At least best friend Sarah still has her back, but as Trina wearies of Morgan's constant insults and her heartless treatment of Knight, she decides to use her dog training skills to look underneath Morgan's hostile attitude and develop a sense of trust.

Slowly, Morgan's angry shield cracks enough to where she's able to share a troubling family secret. Can Trina help Morgan confront her family problems and make a fresh start?