Moriarty the Patriot OVA

A rash of abductions of young boys that end up brutally murdered is plaguing London, and police are powerless to stop it. When William Moriarty discovers a clue linking all the victims, he and his brothers take an interest in the case.

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.