Claudia, the eldest daughter of the Rosenheim family, and Issac, the eldest son of the Lampertz family, are childhood friends who have been bickering ever since they were children. Whenever they see each other, they fight and argue… but they have skipped the “enemies to lovers” part of the story, and go directly to “engaged to marry” instead! It's because Claudia's magical powers are going out of control, but how will Issac help her…!? (Source: 7iro Comics, translated)

Mathematics are erased from Japan school curriculum. Then an organization appear to be the one to oppose that idea, called Black Triangle, threats the government that the organization will take over the country. To fight them, police forms a team, and among them there is a junior high school girl.