At the end of the 19th century, the young mathematics professor William James Moriarty and his allies have decided to take on the British Empire in an effort to destroy the discriminatory class system and create an ideal country. During one of their missions to deliver punishment to the corrupt nobility, William meets a peculiar and intriguing consulting detective named Sherlock Holmes.

William James Moriarty, now known as the "Lord of Crime" to the public, and his allies are still working towards an ideal country by punishing the corrupt nobility. One day the government branch MI6, led by his brother Albert, is given the mission to eliminate a woman called Irene Adler for stealing confidential documents. In the meantime, Adler makes contact with Sherlock Holmes, who has become captivated by the mystery of 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.

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.