The book follows Lucas Corso, a book detective who is hired to authenticate a rare manuscript by Alexandre Dumas. As he delves into the investigation, he finds himself entangled in a mystery involving two other books: a rare edition of "The Three Musketeers" and a satanic text, "The Book of Nine Doors of the Kingdom of Shadows". The narrative becomes a complex puzzle as Corso uncovers connections between the books, while also dealing with a seductive woman who seems to have stepped out of a Dumas novel, a mysterious killer, and a group of bibliophiles obsessed with Dumas. The lines between fiction and reality blur as he gets closer to the truth.

This novel is a thrilling blend of mystery, horror, and fantasy, revolving around a struggling writer who becomes the target of a secret society known as "The Thirteen Ladies". These shadowy figures have the ability to manipulate reality through the power of words and storytelling. As he is drawn deeper into their world, he must uncover their secrets and find a way to survive their deadly games. The narrative is a rich exploration of the power of language and mythology, with a suspenseful plot that keeps readers on the edge of their seats.