William James Moriarty and Sherlock Holmes both become entangled with the ruthless "blackmailing king", Charles Augustus Milverton. Both determined to deal with him, Sherlock finally comes face to face with the mystery he's chased and longed for: the Lord of Crime.

Whitechapel, the slums of the East End in London, are being terrorized by a brutal serial killer called Jack the Ripper. While William James Moriarty receives a letter of request from his old teacher Jack Renfield, the Scotland Yard inspector Lestrade also seeks out Sherlock Holmes and John H. Watson for help in this matter.