Irene Bae was truly in love with a man named, Oh Sehun. Irene, had to left Sehun for some reason. And the other hand, Sehun was one miserable person. But what if the time had come when someone had to left permanently? Will they ever find a way to bring back the past they had, when everything was still perfect? Or is it too late because someone had to be the one that got away?