After a carefree pirate existence, Lily, now reunited with her parents, is having trouble coping with life ashore. So she's overjoyed to see the motley crew from the Mermaid, who, believing her to be dead, have come to return her belongings, including the precious horde of pearls, to her mother. their surprise at finding Lily alive is only topped by their discovery that man they knew as Hussein Reis is Lily's father. James Swann receives word from the Admiralty that he is needed to fight the French on Malta. taking the Mermaid, its crew, Lily and the rest of the Swann family (still feuding), he sails to Malta to help its people rid the islands of the invaders. their mission, to find a way through the secret tunnels under the fortress of Valletta to rescue the Maltese hostages kept there, is betrayed by a trusted friend, and Lily's constant fights with her father threaten to undermine the whole operation. But worse is in store as Lily and her brother Lucas are chased through a wild storm at sea by their old enemy, Captain Diablo ... Ages 9-12