New York City is a violent place. When an out-of-town woman is kidnapped and brutally murdered in what seems like an isolated attack, the story quickly disappears off the front pages of local newspapers. A few days later, nobody remembers the poor victim. Except for John Levy.

John is an aspiring author, and for the past few years, he's been trying to finish his debut novel about a serial killer, Luca, whose quest is to become Lucifer himself. Luca believes that twelve demons possess the bodies of ordinary people and, by collecting them all, he can ascend to the throne of the fallen angel.

To John's horror, he finds a connection between the story of the fictional Luca and the actual murders in the City That Never Sleeps. And if the woman whose picture John saw on the news is the same as in his manuscript, the actual killer is just getting started.

Too terrified and confused to go to the police, John hires a private investigator, Alexandra (Alex) Watts. Together, they race to stop the killer before he strikes again and before John or the entire world around him descends into the abyss.