In the world of antiquity and the occult, a collector of bibliographic rarities embarks on an intriguing mission. Dean Corso, a shrewd and somewhat cynical expert in ancient books, is hired by an enigmatic millionaire to verify the authenticity of a mysterious text that promises to summon the devil. This work, said to have been written by a famous Satanist, is in his possession along with two other copies, and Corso's task soon becomes a deadly game.
As he delves deeper into his investigation, Corso becomes embroiled in a dark world, riddled with secrets and conspiracies that will take him across various European cities. He encounters peculiar characters, including a beautiful woman who seems to know more than she lets on, and a competitor who will stop at nothing to get what he wants.
As he unravels the mysteries behind the books, Corso begins to doubt his own sanity and faces forces that challenge logic. The line between reality and fantasy blurs, and what started as a simple assignment soon transforms into a dangerous adventure that jeopardizes his life. In his quest to uncover the truth, he is drawn into a dark game of deceit and manipulation that will test his loyalty and his very existence, confronting a revelation that will change his life forever.