In this series, South Korea has transformed into a constitutional monarchy. Recently, because the emperor's health is getting worse, in order to fulfill his father's wish, high school prince Lee Shin (played by Joo Ji-hoon) promised the queen mother that he would marry the woman he had previously engaged to as soon as possible. In fact, Lee Shin had been secretly dating the girl Hyo-rin for a while without telling anyone else. When he proposed to Hyo-rin, Hyo-rin flatly rejected him. Although Lee Shin lost his lover, he still felt a little relieved that Hyo-rin would not become a puppet who lost herself and was controlled by others in the palace. The girl who was engaged to Lee Shin was a high school student Caijing (played by Yoon Eun-hye). Her family was just one of the ordinary families in South Korea. They were neither rich nor high-ranking officials. Even when Grandpa mentioned that Caijing and the Crown Prince were engaged many times, everyone thought he was just dreaming. It was not until Caijing's family received a letter from the royal family that everyone realized that Grandpa was not bragging! While Chae-kyung's family was cheering, the maverick Chae-kyung announced that she would refuse this arranged marriage. However, her family's difficulties forced her to accept the marriage reluctantly. At this time, Lee Yool (Kim Jung-hoon), the son of Crown Prince Hyo-yul who died in a car accident 14 years ago, returned to the palace to fight for the throne. What kind of waves will Chae-kyung, the maverick new queen from a civilian family, stir up in this battle for the throne?