A housewife, Mirei, lives with her husband and daughter's family of four. Although she leads a comfortable life, she has been having an affair due to the estrangement in her nightlife with her husband. One day, Mirei accidentally discovers a video featuring her son-in-law, Yoshikazu, at a love hotel. Intending to investigate the truth for her daughter's sake, Mirei ends up revealing her own affair to Yoshikazu. 'If you want an affair, do it with me!' Yoshikazu insistently demands, wielding his young penis. Despite being his mother-in-law, Mirei possesses beautiful skin and ample breasts, driving Yoshikazu's desire uncontrollably. The two find themselves trapped in a quagmire of familial adultery...
