Mariko, who is frustrated due to lack of sex with her husband, secretly consoles herself during her troubled days. One day, she finds out that her son-in-law, Shinji, who lives with her, secretly masturbates for the same reason... Mariko was captivated by the non-standard big dick that she happened to see, and she told herself that it was to make her vent on behalf of her daughter, and she secretly took advantage of him day and night. He continued to tempt her.