Following the Industrial Revolution, Paris develops into a contemporary metropolis in the 19th century. However, in Jun Mochizuki's manga adaption The Case Study of Vanitas, which is based on the same name, the capital's prosperity is overshadowed by the crimes of a bloodthirsty serial murderer who has not yet been apprehended after his ninth victim.
Noé, a teenage vampire from the countryside, is drawn to Paris amid the overall unrest. His previous instructor informed him that the location of the alleged "Book of Vanitas" had been verified. In a children's story, a vampire named Vanitas, who was born under a blue full moon and expelled by his other vampires, left behind this miraculous paper. The book is claimed to give vampires the ability to curse and experience excessive bloodlust because it is filled with the desire for retribution of its author.
However, Noé and his melancholy cat Murr get into an accident on an airship en route to the city. A young human with the name of the exiled vampire and what appears to be the sought-after grimoire approaches them.
