Nineteen-year-old identical twins Violet and Daisie Chettle can hardly believe their luck when they are recruited as maids on newly crowned Queen Elizabeth II's royal ship. Life below deck is hard-work, and whilst Violet is prepared to keep her head down and be seen and not heard, Daisie has her sights on doing everything she can to hang up her apron and mingle above deck. But as Daisie begins to win royal favour, she receives a letter from London. The sisters can't outrun their past any longer - Violet has committed an unspeakable act of betrayal that will change their relationship forever.