London 1888. Angels inhabit every public building, and vampires and werewolves walk the streets with human beings in a well-regulated truce. A utopia, except for one thing: Angels can Fall, and that Fall is like a nuclear bomb in both the physical and metaphysical worlds.

Dr J. H. Doyle returns to London having been wounded in Afghanistan by a Fallen, and finds himself lodging in Baker Street with the enigmatic angel Crow.

But living with a rogue angel is not so easy; the pair find themselves drawn into the supernatural and criminal worlds of London, from a man kidnapped by a vampire nest to Jack the Ripper's horrific murders. Besides Doyle's nightmares, there is the lingering worry that Crow might Fall...