Office worker and 40-year-old virgin Minoru Sayo lives a simple, perhaps boring, life—at least until the day he is turned into a vampire! Captured by the vampire Itachi, Yamadera is forced to become his servant, but appearing in his moment of peril is the vampire Mei, the true ancestor and strongest of all vampires. Being face-to-face with the one he’s been pursuing for so long causes Yamadera to blurt out his desire to become a vampire too. In response, Mei offers him a shocking contract!