When a catastrophic hurricane devastates Stone Cove Island, everyone pulls together to rebuild. 17-year-old Eliza Elliot volunteers to clean out the island's iconic lighthouse and stumbles upon a secret in the wreckage: a handwritten letter. On first glance, it hardly makes sense. But she soon discovers it's an anonymous confession to a 30-year-old crime: the unsolved murder of a local teen named Bess Linsky. Soon Eliza finds herself in the throes of an investigation she never wanted or asked for, and one where everyone is a suspect.