In the late Goryeo Dynasty, which unified the Korean Peninsula, in order to achieve stability in Goryeo, which had been devastated by the long war, King Chungnyeol entered into a strategic marriage with a princess of the Yuan Dynasty in his forties and gave birth to the crown prince Wang Seok. The idle King Chungnyeol indulged in wine, sex and hunting all day long. Every time he went hunting, he would burn the people's fields, causing complaints from the people. When he grew up, the crown prince Wang Seok (played by Im Siwan) became a handsome man and was determined to change the chaos in the country. In order to ask for guidance from the great scholar Dong'an Jushi Li Chengxiu, the crown prince and his friend and bodyguard Wang Lin (played by Hong Jong-hyun) visited his residence and met Yin Shan (played by Im Yoon-ah), the lady of the richest family in Goryeo. The three of them did not know each other and became close friends. In the process of dealing with the complicated struggles between the court and the harem, the prince discovered his feelings for Yin Shan. However, Wang Lin couldn't bear to see Yin Shan selecting palace maids, so he let his sister Wang Xun marry the prince instead of Yin Shan... How will the love between these young people blossom and bear fruit in the chaotic court? Can the emotionally frustrated prince realize his long-cherished wish of working hard to govern the country?