Poppy has found love with Prince Casteel, but their happiness is short-lived. They must embark on a dangerous mission to free his brother and find hers, a quest that will reveal Poppy's true destiny as the rightful ruler of Atlantia. As dark secrets surface and a forgotten power threatens everything, Poppy must decide whether to claim her birthright or forsake it, all while facing betrayal and the machinations of the Queen of Blood and Ash.