The main character, SeoYeon, had the perfect life. She was stunningly beautiful. Boys chased after her and girls wanted to be her. She had two loving parents, a supportive brother, and trustworthy friends. She had everything a girl could ever ask for. One day, she was out with her friends partying on the last day of summer when she met a person… a person who flipped her head over heels in a way she never thought was possible. She made sure that no one could get to her, she never believed in cheesy fairtytales, never believed in the concept of "knight in shining armor," but she couldn't help instantly falling for CNU the first time she laid eyes on him. He asked her to dance with him, and before she even knew what was going on, he mysteriously disappeared, only to reappear a short while later as a transfer student with a cold personality to everyone. Everyone, that is, but her. He didn't even seem to notice all the girls fawning over him. He seems to be secretly watching over her, and he also seems to know something about her, some secret, something big, that she didn't even know herself. Something that could endanger her life and her family. Aside from that, another transfer student comes up. He seems to express feelings for SeoYeon and is not afraid to show it. CNU is not happy about that, but he pretends like he doesn't care. However, that transfer student is also a part of that secret, and he seems to be on bad terms with CNU. As carefree and innocent as he may seem, he's hiding a terrible secret. A secret that involves SeoYeon, CNU, her brother, Jonghyun, and her parents.