One day, Shohei's father brought a young and beautiful woman. Her name was Sanae. Sanae and Shohei eventually became related, and she became Shohei's mother. Shohei lost his mother at a young age, so he was never used to having a woman in the house. It was also living together with Shohei and a beautiful woman whose age did not change much. The stimulation was too strong for Shohei. And that day would come. Shohei could not control his sexual desire and committed a crime with Sana.