男嫌いなクラスの美女が、実はブラコンだと知ってしまった結果。 (Associated Names)

Mizuno Eiji, a siscon high school student, receives the worst news from his older sister: “I have a boyfriend now.” In order to identify the man who stole his sister, he follows her on a date and… sees a suspicious figure watching the two of them as well. That person is Hasegawa Aoi, his classmate…