October 1816 and the body of Harry Gadd, a twelve year old, homeless, street urchin is dragged from lake in St. James's Park. He has been murdered and sexually assaulted. The Bow Street police force, with limited resources, are happy to write this off as another unsolved crime, but Tom Thewles, a newly recruited patrolman, has a very private reason for wishing to avenge his murder. He persuades his partner, Constable Jack Black, to defy orders...