Her husband is away on a business trip, and Kaho lives with her daughter and her husband. Although she is not dissatisfied, she feels lonely without her husband and has to comfort herself. However, she finds out that her son-in-law, Toshiyuki, is using her like that as a masturbation aid... When she accidentally sees his big cock and is given a man's gaze for the first time in a long time, Kaho's crotch gets wet and she can't help but help him release his sexual desire. The frustrated son-in-law can't resist the intense temptations of his mother-in-law, who is unable to suppress her overflowing desire, day and night...