Due to his wife's hospitalization after an accident, Maika Asai, his attractive stepmother, comes to stay at his place to help with housework. Despite being 50 years old, she boasts a voluptuous figure with smooth, radiant skin and soft, firm thighs and buttocks. As days pass under the same roof, the man gives in to temptation, prioritizing his own pleasure. His relationship with his stepmother continues to waver between guilt and desire.