Makoto's heart was disturbed by the lewd moans of his mother, Miki, coming from the bedroom. He knew that his parents were planning to have another child, but he couldn't bring himself to support it. What welled up inside him wasn't the joy of a new family member, but jealousy towards his father for making his mother make such lewd sounds. And it was a desire for possession, not wanting to give his mother to anyone. Every night, as he heard the sounds of his parents' lovemaking, his twisted feelings grew stronger... And finally, Makoto carried out his forbidden plan. It was to fill Miki's vagina with his own sperm and drive out his father's sperm.