Moriarty is Sherlock Holmes told from the villain's perspective, except the villain is right. The show takes that premise and actually commits to it, turning every elegant scheme into a argument about whether systematic evil deserves systematic destruction. You watch Moriarty outthink Holmes not because he's smarter, but because Holmes is defending a rotting system, and by the end you're not sure who the real criminal is anymore.

In late 19th century Britain, the aristocracy holds every advantage while the working class suffers under a rigid hierarchy that measures a life by status and wealth. The wealthy hoard power while the poor are left behind by a system built to protect the privileged. William James Moriarty, an orphan who took the family name when he and his younger brother were adopted into the Moriarty household, lives outwardly as a noble. Working as a consultant for the common people, he grows sick of watching injustice go unchallenged. Beneath that role lies a desire to tear down the class structure and those who profit from it, acting as a crime consultant who delivers justice to the corrupt on behalf of the less fortunate. Together with his brothers Albert and Louis, he is willing to spill blood to change the world. Not even the consulting detective Sherlock Holmes can stop him. The result is a psychological mystery drama that recasts the famous villain of the Sherlock Holmes stories as its protagonist.