When fifteen-year-old Lucy Willows discovers that her father has a child from a brief affair, a eight-year-old boy named Thomas who lives in her own suburban New Jersey town, she begins to question everything she thinks she knows about her family and her life. Lucy can't believe her father betrayed the whole family, or that her mother forgave him, or that her sister isn't rocked by the news the way Lucy is. Worse, Lucy's father's secret is now her own, one that isolates her from her friends, family, and even her boyfriend, Simon, the one person she expected would truly understand. When Lucy escapes to Maine, the home of her mysteriously estranged grandfather, she finally begins to get to the bottom of her family's secrets and lies.