Nightfall - Stephen Leather

"You're going to hell, Jack Nightingale": They are words that ended his police career. Now Jack's a struggling private detective - and the chilling words come back to haunt him. Nightingale's life is turned upside down the day that he inherits a mansion from a man who claims to be his father. It comes with a warning that Nightingale's soul was sold at birth and a devil will come to claim it on his 33rd birthday - just three weeks away. Jack doesn't believe in Hell, but when people close to him start to die horribly, he is led to the inescapable conclusion that real evil may be at work. And that if he doesn't find a way out he'll be damned in hell for eternity.