Junho and Hyoyeon have been dating for a year. But Junho gets involved in an accident where he stays unconscious for a week. He purposely leaves a diary for Hyoyeon to read. Through the diary Hyoyeon finds out that Junho has been cheating on her, but in the end he admits his mistake and truly loves Hyoyeon. But Hyoyeon was hurt and decided to leave Junho.

When Junho wakes up, he finds out that Hyoyeon left him and he couldn't find her anymore. He decided to find her and after 2 years they finally meet each other as co-workers on a company.

How will they deal with each other after all the pain?