Arisa lives with her husband, daughter and husband-daughter couple, and one day, her son-in-law Yohei confides in her that he distrusts her daughter. Thinking of the couple's sake , Arisa and the couple begin to investigate the daughter's background, but as they spend time together, Yohei becomes distracted by Arisa's huge breasts. Gradually, the son-in-law forgets his purpose and is unable to suppress his desire in front of Arisa's obscenely large breasts...