Charlotte Flannigan (Tottie, for short) leads a conventional life in a conventional family. Her father is a well-respected pediatrician, her mother a popular newspaper columnist, and her younger brother a talkative but otherwise okay kid. But on an ordinary Saturday afternoon, Tottie's comfortable life is threatened when the doorbell rings. She answers it to find a teenage boy, who looks eerily like her father, standing there. A stranger, but not quite a stranger. His name is Zachary Pearce, and he is her father's - and not her mother's - son.

Told through the alternating perspectives of Tottie and Zach, Colby Rodowsky's novel explores the ramifications of a sudden change in the makeup of a family. Fear, resentment, desperation, and potential for love all surface in this honest and heartfelt story.