A married woman named Yuri, who married a man with a child. She becomes a stepmother and, though bewildered, leads a happy life. However, she is attacked by her stepson, who has let his feelings run wild. Yuri, awakening as a woman through the passionate lovemaking with the young man's insatiable lust and heartfelt kisses. The once virtuous wife becomes deeply involved in infidelity, indulging in unprotected sex without regard for dangerous days, becoming obsessed with it...