Rin, a newlywed wife starting driving lessons, meets a male instructor younger than her husband. Attracted by his gentle, considerate, and reliable nature, Rin finds her heart pounding uncontrollably when they're alone in the car during lessons. One day, in an empty training room, she confesses her feelings and crosses that line. Seemingly reckless, Rin, and the day after that, in the cramped driving school car, opens her vulva, welcoming the instructor's enormous penis despite being a married woman.