His father remarried the younger Sei, and his son Kosuke got a young stepmother. Sei was beautiful, and Kosuke had a hard time accepting her as his stepmother. One day, Sei saw Sei masturbating in the bathroom, and he couldn't control his desire and embraced her. From that day on, the relationship between stepmother and son fell apart, and Kosuke decided to live alone. The move was in 14 days. However, in the few days left, Sei and Kosuke deepened their forbidden relationship...