Daisuke's father remarried, so he gained a beautiful stepmother named Yuri. He also loves this stepmother very much, and it seems that his feelings for his mother have surpassed filial love... Every time he sees his father being intimate with his mother, he gets angry, witnessing his father having sex and ejaculating inside his mother makes him feel lonely, worried that his mother will be taken away by his father and future sibling. Unable to bear it any longer, he made a bold decision, which is to claim his mother as his own! While his father was at work, Daisuke expressed his feelings to his mother. He constantly hugged, kissed, licked all over his stepmother's body, then had sex and ejaculated inside Yuri. Yuri initially resisted, but she also cherished Daisuke, gradually gave in and started this improper relationship with Daisuke. The two continued to have sex with each other when the husband was not present. Some time later, Yuri became pregnant, but she herself did not know whether the child in her womb was her husband's or her stepson's...