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 into their lives. To celebrate both the return of their long-lost friends and the start of their new lives, they invite Sherlock and the rest of 221B to a dinner party. There, Sherlock and William finally reveal the story of the three "missing" years they spent in America.