In 19th-century France, the wife of vampire noble Jean Duchet Godard is murdered in her own home. With the local human authorities unwilling to properly investigate the case, Godard hires a pair of private detectives known to specialize in the supernatural: Tsugaru Shinuchi, a man with a mysterious birdcage; and his partner, Aya Rindou. This enigmatic duo has come from faraway Japan for one purpose—to track down the man who stole both Aya's body and Tsugaru's humanity.