During the chaotic and conspiratorial Joseon Dynasty, King Gwang-hae instructs his councilor, HEO Kyun, to procure him a double. HEO Kyun discovers Ha-sun, a jester who resembles the monarch, and Gwang-hae is poisoned. For now, HEO Kyun has Ha-sun fill in as king until Gwang-hae heals fully, preparing him physically and mentally. At his first official appearance as king, Ha-sun ponders the complexities of the issues argued in his court. Unlike Gwang-hae, Ha-devotion sun's and gratitude for even the smallest employees eventually improves castle morale. In response to this unexpected change in the king's demeanor, PARK begins to question him.