One day, Shohei's father brought home a young, beautiful woman. Her name was Sanae. Eventually, Sanae and Shohei shared the same surname, and she became Shohei's mother. Having lost his mother at an early age, Shohei never got used to having a woman in the house. And living with a beautiful woman not much older than Shohei. The stimulation was too much for Shohei, and the day came. Unable to suppress his rising sexual desire, Shohei raped Sanae.