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.