Unreal City. The Devil's Children, #1

In the dark streets of 1920s London, private detective Christian Le Cozh is the only one foolish (or desperate) enough to take on the a bizarre case from a man who claims his dead wife still lives. But when a string of supernatural revelations lead him to the conclusion that the world is far more dangerous than he ever imagined, he's drawn into a deadly game of cat and mouse that threatens to consume him.
With the help of an Austrian professor and a grief-stricken woman socialite, Christian must unravel the truth behind the accusations and coincidences before he becomes the next victim in this tantalizing tale of noir, horror, and redemption.