While unconscious on a train, Ryouko finds herself experiencing her first molestation. Unable to cry out due to overwhelming embarrassment, she endures the assault, but despite her shame, her body betrays her as she becomes wet and begins to feel pleasure from the groping. Afterward, she can't get the incident out of her mind. Discovering a website for arranging molestation encounters, Ryouko makes the decision to meet a stranger on a train. This is the story of a married woman's descent into secret desire.