結婚10年目、冷めきった夫婦生活を送るめぐり。ある日、宅配でやって来た男性に声をかけられた。その男性は20年前、めぐりに好意を抱く幼馴染の鮫島だった。当時の面影はなく、ハンサムで逞しい男に成長していた。そして夫が留守中、雨の中訪ねてきた鮫島にシャワーを貸したら、偶然にもアソコを目撃してしまう。幼い頃一緒にお風呂に入った時に見た租チンからは、全く想像できない鮫島の大きなアソコに理性を失ったかめぐりは…。

Ten years into her marriage, Megumi lives a cold and stagnant life with her husband. One day, a delivery man approaches her and speaks to her. The man is Samejima, her hood friend who had a crush on her 20 years ago. He's a completely different person from back then, having grown into a handsome and strong man. While her husband is out, Samejima visits her in the rain, and when she lets him use her shower, she accidentally sees his penis. Megumi loses her reason at the sight of Samejima's large penis, which is completely different from the small one she saw when they bathed together as ********…