'Saki' cares about her little brother 'Mamoru' who hasn't been feeling well lately. According to her story, Mamoru, who still doesn't understand the meaning of sex, is being bullied at school. Saki answers Mamoru's depressed question. Saki had told her that she couldn't have sex with her siblings, but when Mamoru caused a certain incident at school, Saki decided to take her side for her cute little brother.
