Ever since her husband was transferred away from home, Reiko hasn't had sex in a long time. Just when she can't calm down from her desire, she accidentally sees her daughter's husband, Tetsuya, who lives with her, with his huge cock... Seeing Tetsuya masturbating alone and feeling lonely without sex, Reiko tells herself, "As his mother, I'll take responsibility and make things easier for him," and when her daughter falls asleep, she pushes him down. From that day on, her sexual desire, which had been suppressed to the limit, explodes, and she plays with his stiff, magnificent cock again and again...