While the boys get to sail off with the new Great Fleet to chase pirates across the Sunrim Ocean, Amy and Airdella are stuck in Chalef for an unusually boring summer. Until an early morning walk down to the docks takes an unexpected turn... Walter and Aaron are forced to play politics as they work with the representatives of the other nations to track down and eliminate the pirates plaguing their ocean. The pirates lead them on a merry chase from island to island, danger to danger...

The deeper they sail into this sea of thieves, the harder it becomes to know who to trust. Or where the greater danger lies - on board the ships or below them.