One day, while my stressful job had just transferred me to another distant location, my uncle decided that I could stay at his neighbor's house, Yumi-san, until I found a new place to live. She was always very serious and worked as a nurse, so she often looked tired even during her free time. However, one night when I accidentally saw her masturbating passionately with a vibrator after finishing her late shift, all my fantasies about this innocent and meticulous aunt came crashing down! Unable to control myself any longer...

遠方への急な異動が決まった僕は、転勤先の近所に住む叔母・ゆみさんの家にしばらく住まわせてもらうことになった。でもゆみさんはとても真面目で看護師という職業柄、普段からストレスも溜まっているのか、いつもピリピリしていた。だがそんなある日、僕は夜勤明けの叔母が夢中でバイブオナに耽っている姿を目撃してしまった！いつもは潔癖でお堅い叔母から想像もできない淫らな痴態に我慢できなくなった僕は堪らず…。