Mizuki Konoe, who usually lives as normal student life, had a secret identity. Once school ends, she calls herself Charlotte Catherine Krue, the nun who slays demons and the devil who tries to invade her world. One day she stumble upon her classmate who’s wandering around in dangerous site who rumoured as the devil nest. There was a demon lurking there and Mizuki had to jump in to protect her classmate, but sadly she gets inflicted by the demon’s curse because of her clueless classmate