Back in the Joseon Era, clowns were seen to be the most inferior. So, to have a low-life taking the place of the king was something unspeakable. 

However, when Joseon was in a state of disorder that brought about power struggles and uprisings surrounding King Yi Heon, a clown named Ha Seon was brought to the palace to take the place of the king. This was only possible because the two looked identical. 

As the king stays hidden, Ha Seon now has to play the part. But he didn’t expect that he would eventually find himself falling in love with the queen, the people, and the country. As he embraced this role, the lowly clown gradually became a true king at heart.