Adapted from a webcomic of the same title, it tells the story of Kim Mi-so (played by Park Min-young), who has been working for nine years as a secretary alongside Lee Young-joon (played by Park Seo-joon), the perfect vice president of a company. She suddenly wants to resign. In fact, Lee Young-joon's feeling for Secretary Kim is beyond a professional one, so he begins to find a way to keep her by his side, and in doing so, it brings out the secret childhood story between them....