Behind the gates of a fabulous Hampton estate, FBI Special Agent Pendergast discovers the carnage of a gruesome crime - a nightmare of seemingly supernatural origin. The smoldering remains of infamous art critic Jeremy Grove, a melted cross branding his chest, are found in a locked, barricated attic. The hoofprint singed into the floorboards and the smell of brimstone recall the legendary horrors that befall those who make a pact with the devil. Reuniting with police officers Vincent D'Agosta and Laura Hayward, Pendergast combs New York hoping for a simple explanation: a villain who is merely a man. But his search takes him beyond the exclusive clubs and luxury penthouses of Manhattan to a crumbling, legend-shrouded castle in the Italian countryside, where thirty years ago four men conjured something...unspeakable.