: An outstanding leader of the criminal world, who can not be caught in any way, is tracking Holmes in Europe. Longtime enemies meet at a steep waterfall and die in a deadly battle.

After marriage, Dr. Watson rarely sees Sherlock Holmes. One evening, the great detective comes to his faithful friend and talks about the London professor of mathematics, Professor Moriarty. Professor - Napoleon of the underworld, entangled in his web all of London. He prepares crimes, makes money for them, finds performers. Moriarty himself is invulnerable, since it is impossible to prove his involvement in crimes.

The great detective entered the battle with the professor. Moriarty advised Holmes to give up the fight, warning that, having destroyed him, the great detective would die himself.

You hope to defeat me - I declare to you that you will never succeed. If you have the ability to destroy me, then I assure you, you yourself will die with me.

Having been refused, Moriarty made several assassination attempts on Holmes, and now, passing all the strands to the police, the great detective decides to temporarily leave for continental Europe. He asks Dr. Watson to go with him.

Having confused the tracks, friends find themselves in Geneva.There, Holmes discovers that the whole gang has been arrested, only the professor has slipped away from the police. Returning to London Moriarty is dangerous, but he will avenge Holmes.

Walking through the picturesque alpine villages, Holmes does not forget about the danger. The great detective reiterates again and again that he would gladly cease his activities if society were spared from Professor Moriarty. He looks back at his life's journey with a feeling of deep satisfaction, because thanks to him, the air in London has become cleaner.

Friends visit Reichenbach Falls. Dr. Watson receives a letter urgently calling him to the hotel to help the patient. The doctor returns to the hotel, leaving a friend alone. Finding out that an error occurred, he runs to the waterfall. There he finds a note from Holmes - he says that he must meet with Professor Moriarty and finally find out the relationship.

My dear Watson, the note said. “I am writing to you these lines thanks to the courtesy of Mr. Moriarty, who is waiting for me to finally resolve issues concerning both of us.”

Inspection of the scene shows that both opponents fell into the abyss, and Dr. Watson recalls his friend as the wisest and most noble of all the people he knows.