Im Yoona, a high school student, thinks that she is the most blissful person in the whole Earth. Despite losing both her parents from young, Yoona is blessed with eight other awesome friends who are also orphans. They treated each other like sisters and they are well-loved by almost everyone. They grew up and stayed together. Her sisters are all attached, except for her. She never believed in love at first sight until she met the love of her life, Kwon Ji-yong. He was a transfer student, who also happens to be her sisters' boyfriend, Junsu's and Taeyang's good friend. Yoona and him clicked almost immediately. It was as though they had known each other for a long time. She knew that she was in love. Soon, Ji-yong started asking her out, making her the most important girl in his world. They loved each other and believed that she/he is the one. Everyone was also envious of this loving couple. However, one day, a devasting news struck. Ji-yong was met an accident. He was knocked down by a car. At that instant, Yoona's mind went blank. Her world plunged into total darkness. Despite having the support from all her friends, Yoona just simply couldn't get out of her own world. Ever since Ji-yong's death, she had vowed in her heart that never ever will she find another guy that loved her so much anymore. She started to keep herself out from all people. Except for her friends. She became an introvert. Her sisters were all worried for her, but nothing they could do, to help her. They knew that Ji-yong was like her everything. Taking him away means her life will be taken away. Time flies. A new school year had started. And Ji-yong had been dead for almost a year already. Still, Yoona refuses to forgo the past. And, Ok Taecyeon, a new transfer student enters in her life. She begins to see Ji-yong's shadow in him. She slowly found herself trap between the past and present. To make things worse, she was let into a shocking news. A news about Ji-yong's death. A news that will change her life. And what about Taecyeon? Does Taecyeon has anything to do with this news as well? Who, in the end, will be the destined one for Yoona?