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Sherlock Bones, the world's most famous detective, and his trusted assistant Dr Jane Catson are heading to Transylvania to solve another case. Clients claim that a mysterious and dangerous ghost has settled in their estate. Bonz is sure that ghosts don't exist. But even he can't find an explanation for the strange sounds and eerie events in the castle. The situation becomes more complicated when Bonz is summoned to London, and Catson has to see the case through on her own. Will she be able to find out the truth? The fourth in the Sherlock Bones series, this adventure book combines a detective story with 28 puzzles - finding differences, number chains, mazes, and more - so that young readers can test their own detective skills.