The protagonist in the novel is a policeman named Detective Gorby, who is given the task of solving the murder. As Hume describes the character's investigative skills: "He looked keenly round the room, and his estimate of the dead man's character was formed at once." The author commented in a later introduction, "All of the scenes in the book, especially the slums, are described from personal observation; and I passed a great many nights in Little Bourke Street, gathering material". At this time, the street had gained notoriety as a place frequented by prostitutes and criminals.