Before he was Sherlock's rival, Moriarty fought against the unfair class caste system in London by making sure corrupt nobility got their comeuppance. But even the most well-intentioned plans can spin out of control--will Moriarty's dream of a more just and equal world turn him into a hero...or a monster?

After three years apart, Louis, Albert, and the rest of the MI6 team are overjoyed to welcome William back home. To celebrate both the return of William and Sherlock and the start of their new lives, they invite everyone to a dinner party. There, the two long-lost friends finally reveal the story of what happened during the years they spent in America.