Sherlock Holmes has determined that there is a diabolical mastermind behind the criminal activities in London. It's Professor Moriarty. The two men of genius pursue each other towards a final showdown.

'The Final Problem' is a short story by Arthur Conan Doyle, featuring his detective character Sherlock Holmes. It was first published in 'Strand Magazine' in December 1893. It appears in book form as part of the collection 'The Memoirs of Sherlock Holmes.' Conan Doyle later ranked "The Final Problem" fourth on his personal list of the twelve best Holmes stories.