Kidou Eita is a first-year high school student, excelling academically and expressing contempt for romantic relations. He lives a normal school life along with Harusaki Chiwa, his childhood friend whom he regards as a younger sister. One day, the school's prettiest girl, Natsukawa Masuzu, suddenly declares her love to him. However, her real purpose is to establish a fake relationship, deterring those around her from asking her out. To this end, she makes Eita her boyfriend over his objections. The carnage becomes even more vicious when Eita's former girlfriend Akishino Himeka and fiancée Fuyuumi Ai are less than amused by the present developments. Original subtitles by rori.