Princess Bubblegum is left with no other option when pirates infiltrate the Candy Kingdom and steal a most precious treasure from underneath her nose. Without a navy (sugar dissolves in water!), Princess Bubblegum turns to the one person she can trust to retrieve the lost item: Marceline! Together with BMO, Marceline sets sail in pursuit as the dread Pirate Queen, where she faces deadly sea monsters and more in her quest to reach the fabled Domekicker Islands.