Sharper than a Serpent's Tooth. Nightside Book 6

Private eye John Taylor is facing his most dangerous foe yet: his mother. She created the Nightside, and now she intends to obliterate it. The Nightside is the supernatural heart of London, a dark place full of dark, shady characters, a corrupt place, where both dreams and nightmares come true, where anything can be bought for the right price, and where it is forever 3 a.m. But to private detective John Taylor the Nightside is home, and he won't allow his home to be destroyed - even if he has to defeat his own mother to save it.
He may be the only person able to stop her from exterminating the Nightside, a place she created - but there's a prophecy which says no matter what action he takes, not only is the Nightside doomed, but the rest of the world will soon follow... Nothing is ever simple. Sharper than a Serpent's Tooth is the sixth title in Simon R. Green's New York Times bestselling Nightside series.