Yuji, who grew up in an orphanage and never knew the warmth of a family, struggled to fit into the warmth of his wife's household. However, only his mother-in-law, Yukie, treated him with kindness. One day, Yuji accidentally witnesses Yukie masturbating. With both of them feeling unfulfilled, it was only a matter of time before they entered into a lewd relationship. Their secret affair continued without the rest of the family ever finding out.