With two months left before his wife's due date, her mother Mayuka comes to stay and help around the house. The home grows calmer, but tension remains because his wife has caught him masturbating and banned him from doing it again. Unable to resist his alluring mother-in-law, he sneaks into the bathroom area and smells her underwear while she bathes. He becomes so absorbed that he never notices Mayuka has caught him, setting the stage for repeated impregnation sex.