The Goryeo King (played by Joo Jin-mo) faces immense pressure from the Yuan Emperor to produce a male heir to secure the throne. Failure to do so means the Yuan Dynasty will appoint a successor, effectively ending the Goryeo royal bloodline. However, the King harbors a deeply ingrained secret: he is homosexually inclined and unable to consummate his marriage with his Yuan-born Queen (played by Song Ji-hyo). The Forbidden Love Triangle
: The King (Joo Jin-mo) is married to a Yuan Dynasty princess (Song Ji-hyo) but cannot produce an heir because he is in love with his chief royal guard, Hong-rim (Jo In-sung).
