In 1866, a brilliant young orphan and his ailing younger brother are taken in by a charitable aid organization, where they catch the attention of the son of an earl, who is discontent with Britain’s class system.

Albert invites the brothers to come live at the Moriarty’s estate, but the pair are not warmly welcomed by the other members of the household. Albert grows increasingly disturbed by his family’s intolerance, and resorts to drastic measures.

William begins teaching at a university, and is invited to dinner at the home of the Viscount of Belfor. He and his brothers receive a tour of the viscount’s well-kept conservatory, but are taken aback by what they hear of the gardener and his wife.

William learns that Lucian, one of his students at Durhnam University, hasn’t returned for three days. What’s more, the waitress Lucian had vowed to love throws herself from a bridge and dies. However, one of the university’s administrator assures William there’s nothing to worry about, but William disagrees and begins to investigate Lucian’s last movements.

A commoner is chased down by a hunter and his dogs before being shot. The ocean liner Noahtic begins its maiden voyage and Count Blitz Enders, an openly arrogant noble, heavily criticizes that commoners are allowed aboard. Days previously, William shared his plan to slowly remake society by plunging London into an era of crime, all while committing murders designed to educate commoners in exactly how the nobility have been abusing them, starting with Blitz.

Moriarty pretends to believe Blitz’s lie that he killed Thomas in self-defense and offers to cover up the crime.

Sherlock Holmes gets in trouble with his landlady Mrs. Hudson for not paying his rent. Holmes’ friend, Dr. Stamford, suggests Holmes get a flatmate and sends Dr. John Watson, whom Holmes deduces is a retired army doctor. Mrs. Hudson is impressed enough to allow Watson to become Holmes’ flatmate. Inspector Lestrade of Scotland Yard arrives and arrests Holmes for suspicion of murdering Count Drebber.

Sherlock and John, searching for the true criminal who killed Count Drebber, set a trap for the criminal using the wedding ring they found at the murder scene. Sherlock is able to deduce who the real killer is, who offers Sherlock a strange deal.

Sherlock is frustrated because he thinks there’s a mastermind behind the Noahtic and Drebber cases whose identity eludes him. Returning on a train after an unsatisfying investigation into another aristocrat’s death, he happens to meet William again.