A sheltered adult college student who has just moved to the city is so timid she apologizes even while being groped on a crowded train. As she squirms, her slim figure and surprisingly huge breasts become impossible to miss. A middle-aged man watching reaches his limit and grabs them, while she struggles to make a sound. Trapped in silence, she trembles and climaxes repeatedly from sensations she has never experienced, ending with the thought that she may keep commuting by train a little longer.