King Gwang Hae doesn't trust anyone, constantly thinking he'll be poisoned or killed. When he comes across a clown named Ha Seon who looks exactly the same, he decides to put him in his place for a while. It's not easy for Ha Seon to adjust to the palace life and soon, the real danger comes.
Both films tell a fictional story of a Joseon king/prince switching places with his doppelgänger. However, the look alike is a poor man, and thus his upbringing causes plenty of amusing situations in the royal palace.