Simon Spurrier's A SERPENT UNCOILED

I'm going to want a copy of this:

Dan Shaper's sins are a sickness.

Working as a fixer in London's criminal underworld has brought him to the edge of breakdown, and the drugs don't bury the nightmares like they used to. He needs to straighten-up and rebuild his life, but instead gets the attention of his old gangland masters and a job-offer from George Glass: an eccentric old man convinced he's secretly an ancient Messiah. Normally Shaper would recoil from Glass's senile brand of New Age salvation, but the case is as tantalising as it is lucrative:

A missing mobster. A bizarre spiritualist society. Three accidental deaths, unconnected but for a chilling forensic detail. And a note:

"You're on a list."

Adrift amidst liars and thugs, Shaper must push his capsizing mind beyond its limits: stalked not only by a unique and terrifying murderer, but by the ghosts of his own brutal past.