The film explores the three months leading up to Choong-nyung’s ascension to the throne as Sejong the Great. This pivotal time is notably absent from the Annals of the Joseon Dynasty, which chronicles the dynasty’s history from 1413 to 1865. Although he would later be celebrated as King Sejong, the visionary who developed the Korean alphabet and propelled the nation’s scientific and legal advancements, Prince Choong-nyung was initially seen as a withdrawn intellectual. When his elder brothers, Yangnyeong and Hyoryeong, fail to meet the expectations of their father, King Taejong, the king decrees that Choong-nyung should become the next monarch.