In Paris, even vampires deserve a quiet night. Germain Dupré—a centuries-old PI, connoisseur of fresh blood and solitude—has somehow inherited the world's worst co-owner: Romane Bourgeois, a 19-year-old heiress who's 10% yoga, 90% chaos, and 100% convinced his "adorbs" demonic cat is just "going through a phase". But when Nadine Leroy storms into his crypt-like office with a check and a photo of her missing husband (Robert, an antique dealer who specialized in cursed relics), Germain's peace evaporates. The case reeks of: A medieval embroidery covered in Celtic knots (his masterpiece, stolen centuries ago). A codex so shady it makes Hell's playbook look wholesome. Zagan, a mysterious entity crammed into a dancer's body, who offers a deal: "Help me burn the codex, and I'll grant your deepest wish. Refuse… and Paris becomes my playground." Between patching doors busted by goons and enduring Romane's forced cheeriness, Germain must: Decrypt why shadowy figures and art collectors would kill for a dusty old book. Stop Zagan from playing apocalyptic pyromaniac. Hide the truth from Romane—especially about her "kitten". For fans of: The Dresden Files meets Locke & Key in a Paris where the past never dies… it just redecorates Germain's basement.