I realized it was love the moment that person left. Hiding their feelings for each other, Sehyuk and Yina, who were just friends, eventually end their ambiguous relationship and part ways. Eight years later, Sehyuk, who hears about Yina’s engagement, realizes that he hasn’t moved on… Youthful days that can’t be reversed, a romance of two people who had to live resisting their strong attraction towards each other.