Sharper Than a Serpent's Tooth: Nightside, Book 6

"The name's John Taylor. I'm a PI for hire in the Nightside, the dark and corrupt city within the city of London. Where the sun never shines and where pleasure and horror are always on sale - for the right price. Not a nice place to visit or a nice place to live. So you wouldn't think I would care that it was about to be destroyed, but none other than my very own long-missing, not-quite-human mind.

"But I do. I was born here, I live here, and I got friends here. They might not be acceptable in polite company, but they're my friends nonetheless. I know that I'm the only one who can stop her. The trick is, how to do it without fulfilling this prophecy that says whatever action I take, not only is the Nightside doomed, but the rest of the world will soon follow...."