1944. With deadly doodlebugs terrorising London, Bessie Rushbrook agrees to give shelter to eight-year-old evacuee, Marigold, in her Norfolk home. However, the little girl is no stranger, and Bessie must honour the promise she gave to Marigold's mother, Grace, and not reveal her connection to the child. Marigold's arrival stirs up Bessie's memories from the past when the world was at war the first time. She is forced to face her actions from those days and question the haunting secret that she's long kept hidden. When Grace is injured in London, Bessie makes the heart-wrenching decision to confess her secret, knowing that it could destroy everything she holds dear. Will those who love her understand, and can they forgive her?