Shinobu is an office worker, fed up with the tedium of her commute and the incessant fondling that happens to her.
Unable to sit by in silence, a university student uses his body as a shield between her and the deviant but unexpectedly winds up in a precarious situation - it appears as though he is the one that ends up doing the fondling!

Shinobu, realizing he had been protecting her, goes along with it.
"Don't worry, it's consensual," she says.

Unable to move properly, they secretly "fondle" each other on the train.
Once they notice how close they are to each other, they simply can't stop feeling more and more aroused...

After being teased for so long, they can no longer contain their desires through reason alone and end up having sex.

On the train: teasing each other while unable to move away
In the bathroom: SEX!
Train-themed love hotel room: pretending they're still on the train for another round