Demons called "wych-kin" haunt and infest Victorian London, and one has possession of Alaizabel Cray. Thaniel Fox, a 17-year-old wych-hunter, wants to find the Fraternity that has kidnapped her and remove this evil spirit. "Eerie and exhilarating," according to the SLJ, Wooding's novel has been hailed by The Guardian of London as "Intelligent, atmospheric, and spine-tingling... breathtakingly brilliant."