Struggling race car driver and salesman, Denny (Milo Ventimiglia), picks out a golden retriever puppy from a littler and names him Enzo (voice of Kevin Costner). Denny introduces Enzo to the world of racing and the little dog soon loves it as much as his owner.

Denny goes on to meet Eve (Amanda Seyfried), and they fall in love and get married. They have a daughter, and as the years go by, their lives seem idyllic. That is, until Eve is diagnosed with a brain tumor.

Based on the novel by Garth Stein.