In 19th-century France, the vampire aristocrat Jean Duchet Godard's wife is tragically killed within their residence. Faced with apathy from the human authorities, Godard enlists the help of two occult investigators: Tsugaru Shinuchi, the enigmatic man with a cryptic birdcage, and his partner Aya Rindou. Hailing from distant Japan, this mysterious pair embarks on a mission to apprehend the individual responsible for not only robbing Aya of her physical form but also stripping Tsugaru of his very essence.