Taking its name from the poem Yongbieocheonga that says that trees with deep roots do not sway, the series tells the story of a royal guard (played by Jang Hyuk) investigating a case involving the serial murders of Jiphyeonjeon scholars in Gyeongbokgung while King Sejong (played by Han Suk-kyu, in his TV comeback after 16 years of solely film work) comes to create the Korean alphabet.

Dam, who has a photographic memory, becomes a court lady called So-yi (Shin Se-kyung), but she feels so guilty about her role in the other slaves' deaths that she becomes mute.

The deaths were caused by a secret society called "Hidden Root," which was created long ago by followers of Jeong Do-jeon, with the goal of giving more power to ministers and less to the king.

Jeong is able to stop the king's dissemination efforts, and on the day the alphabet is to be publicly announced, both So-yi and Chae-yoon are fatally wounded by Hidden Root members.

Source: AGB Nielsen Korea It aired in Japan on KNTV from 24 July to 17 September 2012,[5] which was followed by reruns on terrestrial network TV Tokyo.