HUNTC-660 Observing the daily lives of schoolgirls for whom commuting in school swimsuits has become the norm. At an all-girls' school in a certain town, attending class in a school swimsuit is mandatory. The girls ride the train, attend lessons, have fun, and have plenty of sex—all while wearing their swimsuits, just as they always have.

At this school, standard school-issue swimsuits became the official uniform when the season shifted to summer attire. While there was some initial bewilderment, the girls soon found them surprisingly comfortable and popular. Naturally, since they serve as the uniform, the girls put them on at home and wear them while commuting to school by train. To an outsider, it is a bizarre spectacle, but for the locals, it is just an ordinary part of daily life. That said, it is undeniably a highly stimulating sight for the male teachers. Naturally, some girls take advantage of this to play pranks, putting the teachers' sense of ethics to the test every day. Yet, beneath the surface, those teachers are merely men driven by male instincts. Mistakes are bound to happen. After all, no man could remain unmoved by the sight of so many cute girls clad in school swimsuits! So, if the school life inevitably turns lewd... well, that’s just how it is.