Sae, whose husband is sexless and who has a lecherous nature, is frustrated with sexual dissatisfaction. One night, as Sae was about to go to the toilet, she noticed light leaking from her son's room. She opened the door and peeked inside, only to see her son masturbating with his fully exposed penis. From that day on, Sae couldn't stop thinking about her son's rock-hard big penis and couldn't focus on anything else, eventually leading to a forbidden relationship with him...
