In their most monstrous case yet, Conan and his friends dress up as famous monsters for a murder mystery game set on a creaky ghost ship. It's an evening of spooky fun-until a real murder interrupts the game. Then it's up to Jimmy Kudo to figure out which rubber mask hides the face of a killer! But there's more than one monster on the loose. Faced with evidence that the Men in Black have discovered their real identities, Conan and Anita have only one hope: find the deadly assassin Vermouth before she finds them. Can they unmask the Syndicate's top mistress of disguise?