This is the story of a brother and step-sister Mitani Akari, with who he grow up together and they are very close. One day Akari receives a letter from the ministry of health, regarding a new law that forces her to get married, in order to bear children and help the declining birth curve of Japan. The stepbrother gets very emotionally involved and visibly irritated by the appointed husband, Taku, an asshole middle-aged guy that began to behave like a creep during the wedding ceremony…