뿌리깊은 나무

Lee Do is the third son of King Taejong of the Joseon dynasty. He becomes Sejong the Great, a well-known king with brilliance, but he is deeply traumatized as he has seen massacres committed by his father since he was young. Being a workaholic and an insomniac, he strives day and night to understand ordinary people and become a righteous king. Chae Yoon comes from a family of slaves, but he has become an officer working in the Royal Guards. He thinks his father died because of Lee Do and plans to take revenge on him. So Yi is the court maid that Lee Do's son loves. Although aphasic, she is smart, insightful, and passionate about creating the Korean alphabet. Ki Joon earns Lee Do's trust and gets involved in his project to create the Korean alphabet, but he secretly plans to stab Lee Do in the back. With all these people entangled with each other, serial murders happen at the palace, and the project to create the Korean alphabet doesn't go smoothly.