Akio works at a convenience store. Yukio, his younger brother, always comes to his store after work. He is actually a teacher at a girls school. What they do is to punish girls who committed shoplifting. One day, Yumi comes to the store and looks for a toilet. Yukio takes her to the toilet and secretly puts an article for sale into her bag. When she comes out, Akio stops her and checks her bag...