WARNING: The following contains spoilers for Episode 17 of Moriarty the Patriot, "The Riot in Scotland Yard," now streaming on Funimation.
In the third installment of Moriarty the Patriot's Jack the Ripper arc, "The Riot in Scotland Yard," Scotland Yard claims to have finally apprehended the notorious killer, aka 'The Phantom of Whitechapel.' But Lestrade, Sherlock and the Moriarty gang know the truth: the Chief of the Yard, the poor-hating Arterton, has knowingly arrested a patsy for the crime in order to bring an end to the civil unrest rocking London.
As the various parties work to prove that a wrongful arrest has taken place, the consulting detective's involvement also cements his other lingering suspicion concerning the Lord of Crime's true motivation.
In Episode 17, Arterton's officers are busy doing what crooked cops do best: beating a confession out of their prisoner that will -- due to the unreliable nature of torture -- be a falsehood. Luckily, Lestrade isn't the only person at the Yard speaking out against the miscarriage of justice. Inspector Paterson, a minor character from the original novels, accepts the Moriarty family's help in obtaining the evidence needed to clear the prisoner's name -- a ledger in Arterton's office containing proof enough of the frame job. Bonde runs point on the case, using his effortless thieving skills to sneak in and out of the office and pass the ledger to Paterson while Sherlock and Watson do their own snooping elsewhere, looking to verify the Lord of Crime's involvement in solving the Jack the Ripper case without interfering in the criminal's continuing plot.
Eventually, their combined efforts are sufficient in bringing Arterton's corruption out of the shadows. Publicly named and shamed, the CID is removed from office, ushering in a new era for the organization under Paterson, the 'New' Scotland Yard. Reading about the turn of events from the comfort of his home in a newspaper, William Moriarty confirms that removing the rot from London's foremost policing establishment was yet another piece of a steadily assembling, wider scheme of his: "The time to execute the Moriarty Plan is coming soon." Now that they have a man on the inside in Paterson, too, he's even more assured that whatever he's plotting will come to fruition.
But before Episode 17 ends, Sherlock draws his own conclusions on the Lord of Crime's lofty goals, examining the anonymous crime boss' fingerprints across the recent spate of scandals and socio-political upheavals and correctly describing the "favorable" way he helped solve them as akin to a Robin Hood figure. In other words, the detective is aware of the nuances of his elusive adversary. Naturally, he can't ignore the fact that they are still a criminal, leading him to further ponder that simply rescuing an innocent man must be of benefit to the mastermind in some way. Figuring out what that benefit is will be key to Sherlock finally working out the Lord of Crime's master plan.