She loves bananas! The aho-girl, Hanabatake Yoshiko, who doesn’t care if she can’t do her studies at all, starts yet another day at school. Her carefree actions of idiocy seems to not only cause trouble for her childhood friend, A-kun, but her classmate, Sumino Sayaka, as well.

Yoshiko, self-proclaimed "master player," goes to the park. She immediately starts playing with the kids, but the kids can't help but show surprise and confusion at the games her idiot whims bring her to play. Kurosaki, a delinquent, joins the mix, and the disciplinary committee president who can't keep her fantasies in check control appears. More idiots just keep coming!

Sayaka visits the Hanabatake house! But awaiting her there was none other than Yoshiko's mother, Yoshie. Fearing that Akuru might be stolen away by Sayaka, she does what she can to embarrass Sayaka. Yoshiko joins the mix, and what does Sayaka do?

On the night before Akuru's birthday, Yoshiko and Sayaka sneak into Akuru's room to search for a hint on what Akuru wants for a present. The disciplinary committee president hears of their scheme and joins them, but their plans are derailed, with Yoshiko and the disciplinary committee president going after a sleeping Akuru!

Yoshiko wins a vacation in the shopping district raffle and invites Akuru and Sayaka to go with her, but the disciplinary committee president and Ryuuichi catch wind of the trip and ask to go. The topic naturally changes to buying new swimsuits, but then Akuru refuses to go. And a surprising someone swoops in to convince him otherwise!

Yoshiko and friends arrive in Izu Atagawa, change into their swimsuits, and head straight for the waves. The disciplinary committee president tries to flaunt her precious rack, but fails and is buried in the sand as punishment by Yoshiko. Yoshiko goes on rampage and buries Sayaka as well, and starts sculpting some ------- and a ***** on them too!

Emura Akane, Shiina Kuroko, and Hiiragi Himeko are hanging out in the classroom after school when Yoshiko sets her sights on them. The girls, completely unable to read Yoshiko's behavior, get roped into playing with her. They agree to play hide and seek in order to escape Yoshiko, but then...

Nozomi, Masaru, and Mamoru go to buy snacks for their field trip, with 300 yen each as their budget, when Yoshiko tries to initiate them into the finer points of buying field trip snacks. Masaru and Mamoru follow Yoshiko's teachings as they buy their snacks, but Nozomi buys a single expensive snack. Nozomi's field trip will end dark and gloomy... or so they thought!

In order to make the cultural festival that she looked forward to so much a success, Emura volunteers to join the cultural festival committee. Progress on the class attraction is slow, so she and her friends stay overnight at school to get some work done, but then Yoshiko enters the scene. The three girls try to get rid of her, but they get sucked into her game...