Natsuko's son, Kousuke, whom Natsuko raised splendidly on her own, has finally decided to marry. However, Kousuke, who had a secret admiration for his mother, could not shake off that feeling until the very end... On the eve of the marriage, Kousuke's mother gave him the last lesson, "I just want them to be happy..." to Kousuke, who is worried about his new life. Kousuke, who had climaxed many times from his unconditional love, continued to experience the pleasure that he experienced for the first time and continued to experience intense excitement. And the mother and child who dabbled in her forbidden pleasure were trapped in a whirlpool of desires...