In Joseon-era Korea, the nation is under the rule of King Gwanghae, a monarch facing threats both from within his court and from external factions. Fearing for his life after an assassination attempt, Gwanghae orders Chief Secretary Heo Gyun to find a body double who can impersonate him while he recuperates in secret. The search yields Ha-sun, a lowly acrobat who bears a striking resemblance to the king. Ha-sun is trained meticulously to adopt the mannerisms and habits of Gwanghae, enabling him to seamlessly assume the throne temporarily.

As Ha-sun begins his role as the king, he not only has to mimic Gwanghae’s behavior but also navigate the treacherous political landscape fraught with intrigue and deception. With each passing day, he grows more confident in his position, won over by the loyalty of the palace servants and his own innate sense of justice. The commoners’ plight and the palace’s corruption become apparent to him, leading him to make decisions that surprise the court officials. This newfound moral compass causes ripples throughout the kingdom, threatening to expose his true identity and challenge the existing power dynamics.