One day, Shohei's father brought a young and beautiful woman. The name is Sanae. Eventually Sanae and Shohei became the mother of Shohei with their surnames together. For Shohei, who lost his mother early, he never got used to the life of a woman in the house. It is also a communal life with Shohei and a beautiful woman whose age does not change so much. The stimulus was too strong for Shohei. And that day will come. Shohei couldn't control his sexual desire and committed Sanae.