Ruri's days had been dull and monotonous until one day, she unexpectedly encounters a molester on a train. In that instant, fear and excitement intertwine, leaving her unable to speak. As her massive breasts are groped, Ruri's mind gradually succumbs to the molester's control. Even on her way home, the lingering sensation of the incident continues to stir her emotions. That night, while masturbating, she awakens to pleasures unlike anything in her ordinary life. Driven by this new craving, Ruri makes up her mind to board the train once again—knowing the molester might be there.