After weeks of waiting, thirteen-year-old Theodore Story finally spots the billowing sails of the Canterbury, the ship returning Governor William Penn, a close friend of Theo's family, to Philadelphia. During the governor's fifteen-year absence, such wild pirates as Captain Kidd have corrupted the "city of brotherly love." Maybe now things will get back to normal, Theo silently hopes. Shortly after the governor settles in, however, Theo's grandfather dies, and Theo, his mother, and his sister set sail for England. When several members of their ship's crew contract yellow fever, the family desperately hails a passing vessel and transfers over.

But something's not right about this new ship and its ragtag crew. As the cabin door clicks shut behind him, Theo notices it locks from the outside. They are being held hostage by pirates! Theo vows to save his mother and sister, but with escape almost impossible, how can he outsmart the bandits and get word to Governor Penn?

Tag Line: "Am I my brother's keeper?" For Theo, the answer is yes....