Yuji grew up in an institution and had no experience of the warmth of a family, so he couldn't get used to the warmth of his wife's family. However, his mother-in-law, Yukie, treated him kindly. One day, Yuji witnessed Yukie masturbating. It was only a matter of time before the two, who were both unsatisfied with each other, became involved in a lewd relationship. Their relationship continued without their families knowing.