King Ato the Eighth and Roger the Read Bird are at home on Octagon Island; Roger reads to his master while Ato scans the horizon, looking for Captain Samuel Salt and his ship the Crescent Moon. The Captain was supposed to return for them six months after their last adventure; but three years, eleven months, and 26 days have passed, before the Captain finally shows up.

Changes have occurred in Salt's situation. He is a pirate no longer, but now the official Explorer and Discoverer Extraordinary to the Crown of Oz. And he has replaced the troublesome crew of his ship with magical mechanisms that allow him to sail it virtually on his own. He can still use a cook, though; and Ato is happy to take up his old job. Ato, Roger, and the Captain sail off for discovery and adventure.