In the story, the brilliant consulting detective Sherlock Holmes has discovered that nearly all crimes which are committed in London are the work of one gang. The gang is headed by one man, Professor Moriarty, whom Holmes calls "the Napoleon of crime" and acknowledges as his intellectual equal. Holmes has gathered evidence against Moriarty and his gang which should lead to their arrest, conviction and execution. When Moriarty finds out about this, Holmes' life is in danger. Accompanied by his friend Dr. John Watson, Holmes flees to Switzerland. Moriarty pursues Holmes there and confronts him at Reichenbach Falls. Dr. Watson arrives at the scene later and is under the impression that both Moriarty and Holmes have fallen to their deaths.