The happiness of the young man towards his father's wife is thought to be him being happy for his father because there is a new companion to take care of him, but little does he know that the happiness he thinks is about physical contact is actually the incestuous relationship between the stepmother and her stepson.
The movie is good here:
Quick Link: javhd.uk/6670 javhd.uk/code/VENU-902
Movie Code: VENU-902
Movie Studio: VENUS
Actor: Eri Takigawa