Thirteen years ago, Chloe Hale's father passed away, leaving a grave, an old watch, and a never-opened music box. Later, a mysterious man named Cain Lowe appears, telling her the truth of that year is far more complicated than she imagined. As clues emerge, the identities of old friends, family members, and guardians are reversed. Chloe Hale discovers her father left her not just secrets, but also a person who has kept a promise for thirteen years.