Dean Corso is highly skilled at his work, a position which requires dexterity, cultural expertise, nerves of steel... and few scruples. Known for locating rare books for wealthy collectors, Corso is hired by eminent book-lover and scholar of demonology, Boris Balkan. Corson's mission: to find the last two volumes of legendary manual of satanic invocation "The Ninth Gates of the Shadow Kingdom," compare them Balkan's first volume, supposedly the only one of its kind, and ascertain the authenticity of the series. Corso accepts the challenge. From New York to Toledo, Paris to Cintra, he immerses himself in a labyrinth full of pitfalls and temptations, disturbing encounters, violence and mysterious deaths. Protected by an angelic creature and guided by a force more powerful than himself, Corso solves one by one the mysteries of the dreaded Book and discovers the real purpose of his mission.