Recovering from a mistaken medical diagnosis and a failed suicide attempt, former cop Jack Taylor takes a job as a night-shift security guard. But in his 13th outing (after The Emerald Lie), Jack's Ukrainian boss wants him to find what some claim to be the first true book of heresy, the Red Book, currently in the possession of a rogue priest who is hiding out in Galway after fleeing a position at the Vatican. Even as Jack reluctantly undertakes this peculiar mission, Em—the many-faced woman who has had a hold on Jack's heart and mind for the past two years—reappears and turns out to be entangled with the story of the book, too, leading Jack down ever more mysterious and lethal pathways.