A detective tracks a vicious killer through the slums of Victorian London in this "fiercely edgy" mystery that adds grit to the world of Sherlock Holmes ( Booklist ). London, 1865 . The city is terrified. A killer haunts the streets, crime bosses are taking control, and the police force is stretched to the breaking point. Those who have means turn to Sherlock Holmes, but the celebrated private detective rarely visits the streets of South London, where the crimes are sleazier and the people are poorer. In these precincts, victims turn to a man who despises Holmes and everything he represents: his wealthy clientele and his showy forensic approach to crime. Arrowood is a self-taught psychologist, occasional drunkard, and private investigator. When a man mysteriously disappears and Arrowood's best lead is viciously stabbed before his eyes, he and his sidekick Barnett face their toughest quest yet: to capture the head of the most notorious gang in London . . .