On her way to school, Azusa is suddenly groped by a stranger on the crowded train. She desperately writhes to escape, but fear paralyzes her voice. The man reveals himself as a molester, and soon she falls victim to his advances every day. Driven wild, he brutally penetrates her bareback from behind, using her in the train before callously abandoning her. Yet, awakened to pleasure, Azusa begins secretly masturbating at school, fantasizing about the man. Day after day, she finds herself longing for the next assault.