"Journaux sexuels ~ belle-fille : Yuki Jin DVD"

One day, he stumbles upon a DVD that contains a video of his wife and stepfather having sex. The stepson was puzzled, but he couldn't stop watching the video. Why are my stepfather and his wife...? The stepfather, who is ill, comes up with the idea to continue filming his stepson's sex with his wife until he cums. He puts his wife to sleep and films the whole thing. He then uses it as a story to further...