学生時代はモテまくっていた俺だが、社会人になり仲の良かった友達は次々に結婚して離れてゆき、冴えない独身男になってしまった。そんなある日、道端でイイオンナが倒れていたので看病する事になった。そのオンナは、10年前に俺に告白してきた同級生で幼馴染の七緒だった。地味だった当時の面影はなく、美人で巨乳で色気漂う人妻に進化していたのだ。その夜、旦那の浮気を知って家出した七緒が、頼るあてがなく俺の家を訪ねてきて…。

I used to be incredibly popular with the ladies back in my college days, but once I entered the workforce, my close friends started getting married one after another and drifted away, leaving me a dull, single guy. Then one day, I found a gorgeous woman collapsed on the side of the road and ended up taking care of her. That woman was Nanao, a classmate and hood friend who had confessed her feelings to me ten years ago. She bore no resemblance to the plain girl she used to be; she had transformed into a beautiful, busty, and alluring married woman. That night, Nanao—who had run away from home after discovering her husband was cheating on her—had nowhere else to turn and came to my place…