After finishing the School of Witchcraft, the aspiring witch Niko Wakatsuki returns to her hometown to practice. As her familiar she chooses her childhood friend Morihito Otogi, who is a demon, and his ancestors have served witches since ancient times. Morihito himself is not particularly happy about such circumstances, and he has no choice, for if he obeys the witch's orders, the consequences will not be very pleasant. Moreover, Morihito will have to not only obey Niko, but live under the same roof with her.