Since losing her beloved husband, mother Arisa has been living quietly with her husband's child, Takashi. One day, she receives a marriage proposal from Sato, whom she met at work and was dating. Arisa, who was struggling financially, is grateful for this offer and takes it in a positive light, but Takashi keeps insisting, "I want you and Mommy to be alone." After that, Arisa and Sato's relationship deepens further, and the two often indulge in love affairs. However, Takashi's eyes are peeking through the gap... Seeing Sato devour Arisa's voluptuous bust and hips, Takashi's jealousy burns. And he also awakens an abnormal desire for his "mother's" body...