Inspired by the urban craze for escape rooms, where players tackle puzzles while trapped in a locked room, it is an escape room in the form of a locked book, filled with codes, ciphers, riddles and red herrings, and a clever Code Wheel set into the cover.

Taking on the role of Sherlock Holmes, in this new adventure readers find themselves trapped with Watson and aspiring engineer Henrietta Prince in the grand home of Bertram Alfreds, the last surviving child of Lord Byron. After being lured to the residence by an intriguing mechanical music box, Holmes and Watson must find their way through the mansion, foil a deceitful plot to destroy Henrietta's lifelong work - a replica of Babbage's Analytical Engine - and fathom the involvement of Moriarty, if they are to win their freedom and save the day.