Set near the end of the Goryeo era (AD 918-1392), Korea was politically manipulated by the Yuan Dynasty in China. The ambitious King of the Goryeo Dynasty organises Kunryongwe as his royal guards and escorts. Hong Lim, the commander of Kunryongwe, is favoured by the King of Goryeo and the Queen keeps a watchful eye on the their relationship. Meanwhile, the bilateral relations between Goryeo and the Yuan gets worse as Yuan demands to install the cousin of the King as the Crown Prince of Goryeo, attributing to the fact that there is no heir sired by the King. The high-ranking officials of Goryeo, who are in submission to Yuan, are hence unhappy with the King. One day, the King gives Hong Lim the covert and objectionable order to sleep with the Queen in his place to protect the independence of Goryeo from the Yuan by producing a son, the successor to Goryeo throne.