From the writer of the epic historical Queen Seondeok comes another grandiose historical about one of the greatest kings of Korea, King Sejong. Beloved and wise, King Sejong was a man of science and technological advancement than he was of war. His scientific achievements led to the betterment of his subjects’ lives, and increased his population’s literacy level with the development of Hangul, the Korean Alphabet. Veteran film actor Han Suk Gyu makes his return to the small screen as King Sejong, and he is joined by Jang Hyuk and rising actress Shin Se Kyung. In the midst of King Sejong’s rule, he discovers that there is a conspiracy to undermine his power, and that someone is killing off his scholars. He hires police officer Kang Chae Yun (Jang Hyuk) to investigate their deaths, but little does he realize that Kang Chae Yun has a secret vendetta against him too. In the middle of all this is So Yi (Shin Se Kyung), one of King Sejong’s trusted court ladies who is also mute. She is the only one who has the key to the killer, and holds an interesting bond between King Sejong and Chae Yun.