"The Final Problem" – Holmes is on the verge of delivering a fatal blow to Moriarty's criminal ring, but is forced to flee to continental Europe to escape Moriarty's retribution. The criminal mastermind follows, and the pursuit ends on top of the Reichenbach Falls, where the two are involved in a deadly struggle.
Arthur Conan Doyle. Professor James Moriarty is a criminal mastermind whom Holmes describes as the "Napoleon of crime" and considers him his archenemy. Moriarty is a crime lord who protects nearly all of the criminals of England in exchange for their obedience and a share in their profits. "The Valley of Fear" – Holmes gets led to Moriarty by
Moriarty’s obsession with Sherlock peaked when he came up with a very elaborate plan to bring Sherlock down and destroy his reputation, which began with simultaneously breaking into the Tower of London, HMP Pentonville, and the Bank of England, and then turning himself in. Just like Sherlock’s, Moriarty’s mind was very complex, and he got