A cruise vacation for Geronimo and friends turns moldy when the ship iscommandeered by pirates!Benjamin, Trap, and Thea are concerned that GeronimoStilton works too hard as editor-in-chief at the Rodent's Gazette. To gethim away from the office, they decide to investigate the mysterious three-headedbrie-smelling monster that is roaming around the port of New Mouse City. But,things take a turn for the worse, as our heroes find themselves held trappedlike rats on a ship...commandeered by the dreaded Captain Blackrat.

Will it be apirate's life for Geronimo and his relatives? Perhaps a cruise is thevacation he was needing!