Plot

A look-alike commoner is secretly hired to take the place of a poisoned king to save his country from falling into chaos.

Amid national chaos and fear for his life, tyrannical King Gwanghae orders his trusted councilor Heo Kyun to find a royal body double. He hires Ha-seon, a peasant mimic who bears a perfect resemblance to the King. When King Gwanghae collapses from a mysterious poison, Ha-seon reluctantly becomes a King. He must follow his conscience to save his country from collapse, avoid assassination, and pull off the biggest masquerade in history. K—CJ Entertainment

During the confusing and conspirational Joseon Dynasty King Gwanghae orders his councilor, Heo Kyun, to find him a double in order to avoid the constant threat of assasination. Heo Kyun finds Ha-sun, a jester who looks remarkably like the king. Just as feared, Gwanghae is posined. Heo Kyun proposes Ha-sun fill the role as the king until Gwanghae recovers fully and grooms Ha-sun to look every bit like the king. While assuming the role of the king, Ha-sun begins to ponder the intricacies of the problems debated in his court. Being fundamentally more humanitarian than Gwanghae, Ha-sun's affection and appreciation of even the most minor servants slowly change morale in the castle for the better. However, his chief opposition, Park, notices the sudden shift in the king's behavior and starts to ask questions.