In present-day California, Eleanor Bennett’s death leaves behind a puzzling inheritance for her two children, Byron and Benny: a black cake, made from a family recipe with a long history, and a voice recording. In her message, Eleanor shares a tumultuous story about a headstrong young swimmer who escapes her island home under suspicion of murder. The heartbreaking tale Eleanor unfolds, the secrets she still holds back, and the mystery of a long-lost child challenge everything the siblings thought they knew about their lineage and themselves.