Three years after the car accident that killed her 17-year-old son, Nathan, Claire O'Neal clings to grief, her life empty but for imagined conversations with the boy she raised on her own and her hectic job as a San Antonio, Tex., real estate agent. Preston (Butterfly House) strikes an uneven tone in this sentimental novel about loss and letting go. When therapy doesn't help, Claire decides to chase after Nathan's heart, which was transplanted to Mason McKinnon, a concert violinist with heart disease. She tracks Mason down to Sante Fe, New Mexico, where she finds him working as a piano player in a seedy bar, ""wasting his health and a providential talent."" She schemes her way into Mason's life and strives to preserve her son's gift by preparing healthful meals for Mason and hiding his cigarettes. Their friendship survives the revelation of her identity as the mother of his organ donor, and evolves into a strange romance. Awkwardly woven in with this story are peeks at other characters significantly affected by Nathan's death: his high school girlfriend Lindsey and the trucker who's wracked with guilt for his role in Nathan's accident. Preston's well-intentioned novel ultimately offers redemption and healing for its tragedy-stricken characters.