Everyone is finally safe and sound at last, and time to set sail, after the many misadventures on Mirror Island, for Mouseland. The crew learns of a shortcut across the unfamiliar waters of Python Sea, where a strong current carries the Queen of the Winds homeward. And they make good time too, until one day, a terrible splintering sound echoes across the deck and the ship comes to a sudden stop. Something has torn a gash in her hull, and the wounded vessel is tilting to one side as water gushes into the hole. What will become of the Queen of the Winds? And what will become of Rumini, Rosie, Jake, and the others? Does the sunken world of Megantis really exist? Never have Rumini’s adventures begun with such a heartrending tragedy, but neither have he and his friends ever embarked on a voyage which has had so many surprising twists and turns.

Join Rumini and his friends as they face new foes and allies, from corrupt wallaby gendarmes to ruthless mermaid hunters, mermaids, jumping mice, and even deep-sea monsters in their quest to save their castaway friends.