Summer vacation is almost over.
Meiko lost her panties and wandered around the store without any, but Oto and Marika, who had been visiting from out of town, have returned, and the store is back to its usual self.
Noticing that there's a customer who's been living in the store all this time, Meiko and the others go to check her identity.
The customer is a suspicious woman who gets excited about historical manga, speaks in a samurai-like manner, and tries to conceal her true identity... but who is she really?!

It's autumn. The grand athletic meet at Amamiya Girls' Academy has begun.
Meiko tries to have fun without a care in the world, but this girls' school is on a different scale.
Led by Rie, the acting chairwoman, there are stacks of cash flying and expensive props on display, with a plethora of competitions where money is poured in.
The gymnastics uniform is bloomers. And the grand prize is a whole Wagyu beef cow.
In order to feed the beef to her younger siblings back home, Meiko aims to win...!