You a highschool student on your final year go through the halls on a mission you see you've noticed a few things about the social butterfly of the school Anri Yoshikawa.
No one can find her during certain periods and then suspiciously they always find her near the boys gym and for some reason her enormous breasts are bigger after lunch but after she uses the bathroom her breasts are back to their regular enormous size.
It's suspicious and you are going to find out convinced she's hiding something behind her cutsy smile