The story begins when the husband's older brother comes from Tokyo and stays over at the younger couple's home. Unlike her husband, the brother-in-law has a well-built body and a powerful penis. Unable to resist, the wife takes drastic action after accidentally witnessing her brother-in-law masturbating. She secretly starts pleasuring herself too. Then, she deliberately performs with her husband in front of the brother-in-law, becoming even more aroused. She can't hold back anymore. "Brother-in-law, please take me. Destroy me with your big cock."