Amid national chaos and fear for his life, tyrannical King Gwanghae orders his trusted counselor to find a royal body double. He recruits a crude, working-class peasant, Ha-seon, a village performer who bears a startling resemblance to the ruler. When the king falls into a coma from poisoning, he is secreted away to recover and Ha-seon reluctantly assumes the throne, forced to pull off history's biggest masquerade.