Chae Gyeong is an ordinary high school student. One day, she receives some unexpected news. Because of her grandfathers will, she must marry the unendurable Crown Prince Lee Shin who also attends her high school. Chae Gyeong resists the proposal but reluctantly marries him to help her debt-ridden family. As she struggles to adapt herself to the proper manners and royal duties of palace life and to her disagreeable husband, Lee Shin's sentimental cousin and second-in-line to the throne, Yul, steps into her life. She feels like she can rely on Yul to help her, but finds it difficult not to worry about her haughty, cold-hearted husband. To help bridge this gap, the senior members of the royal family take some special measures to get them to spend the night together.