Boogiepop Doesn't Laugh

In order to go to high school in Japan, Kirima Nagi's half brother, Taniguchi Masaki, returns to Japan. Masaki gets advice from his sister to not stand out as much at school, but ends up gathering some grudges from some of the kids at school. He gets surrounded by some students and a girl calls out to them. Orihata Aya seems to be offering herself up in Masaki's place. Because of this encounter, the two of them start to get closer, but...