As the city of London began to recover from the terrible crimes that took place three years ago, a bizarre murder set off alarm bells at Scotland Yard. William Brassey, inspector of the police is forced to keep it secret, but letters sent by the killer and the discovery of a mysterious diary will bring a new approach to the investigation. Brassey goes in search of John Nesbit, a policeman cut off from his job and addicted to drinking and slums from the underworld. No one knows the mind of this type of assassin better than Nesbit, but will he be able to dive back into the game of a new assassin?, has "The Monster" returned or is he a simple impersonator? Nesbit must go in search of its past trying not to lose touch with the present. A harrowing journey that will take us into the most absolute decadence of the emerging city of London.