Natsuko's son, Kosuke, whom she raised alone, is finally getting married. However, Kosuke secretly harbors a longing for his mother, and is unable to shake off his feelings until the very end... On the night before the wedding, as Kosuke worries about his new life, his mother gives him a final lesson: "I just want the two of you to be happy..." Kosuke, who has experienced countless orgasms from the unconditional love, continues to be excited by the pleasure he is experiencing for the first time. And as mother and son try their hand at forbidden pleasure, they are caught up in a whirlpool of desire...