Noé Archiviste, a young vampire with a curious heart and a heavy past, arrives in the clockwork splendor of 19th-century Paris searching for a legend known to many as *Vanitas no Carte*. This fabled Book of Vanitas is whispered to be a cursed grimoire capable of annihilating every vampire in existence, yet Noé’s search takes a wild turn when a sudden outburst of madness aboard a luxury airship brings him face-to-face with the book's owner. Instead of a vengeful spirit, he finds a self-proclaimed human doctor named Vanitas, a man who brandishes the glowing blue tome not to slaughter his kind, but to cure them. This chaotic meeting sparks an inseparable partnership, pulling Noé away from his peaceful life and into a vibrant, dangerous world of mechanical marvels and supernatural secrets.

Also known as *The Case Study of Vanitas*, this sprawling steampunk odyssey follows the unlikely pair as they navigate a society where vampires are being corrupted by a mysterious "malnomen" that steals their true names and turns them into monsters. While Vanitas fights a lonely battle against the shadow of the Blue Moon, Noé must reconcile his loyalty to his people with the cryptic motives of the man he has sworn to follow. They are pursued by the fanatical Chasseurs and haunted by the elusive forces of Charlatan, facing external threats that are matched only by their own internal struggles with identity and trauma. Amidst the gaslamp glow and the clash of blades, they remain united by a singular, defiant goal: to solve the mystery of the curse and save a dying race from its own tragic destiny.