Mari lives with her husband and son. - My son's hobby was to spy on his parents' nightly activities and masturbate. - One day, Mari goes to her room to call for her son. - When I opened the door, my son was masturbating. - "It's the worst thing to be seen by my parents," my son says bitterly. - When I tried to convince him that masturbation wasn't something to be ashamed of, he demanded that I show him masturbation. - From that day on, Mari couldn't stop having a relationship with her son. - She drowns in forbidden pleasure with her son...