After three years, the Moriarty brothers visit their Durham residence. The mansion is in a state of decay after years of neglect. As he takes a stroll through the residence, Louis finds the secret diary he had kept back then. Untold incidents left behind three years ago. Now, some them shall be revealed!

William is intrigued when a man in a tavern sees through Moran's cheating and challenges him to a game of poker for a large sum of money. There's also an over-zealous Louis who names the tropical fish he's assigned to keep "William", Albert and Moran compete in a wine-drinking contest, and John becomes a detective instead of Sherlock, and shows off his famous (?) deductions. The daily research records that were not shown in the main story are released for the first time!! (Source: Shueisha, translated)

In this light novel based on the Moriarty the Patriot series, William visits a department store in London to get a present for Louis and Albert when it is suddenly attacked by a mysterious armed group! Together with help from a mysterious girl, William tries to get control of the situation. Meanwhile, Sherlock becomes Gregson’s assistant as he investigates a locked-room mystery! (Source: Shueisha, translated)

When Sherlock is asked to find the son of a nobleman, he enlists William's help to infiltrate the club where the nobleman lives. They get to the bottom of the case, but a hostage taker, a "game enthusiast", forces them to take part in a game of Russian roulette. In four short stories, Bond teaches acting to the Whitechapel troupe, Jack is put to the test when the three brothers become his apprentices, and Sherlock is introduced to a strange case on holiday by Mycroft! (Source: Shueisha, translated)