Deep Rooted Tree
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 Gyeongbok Palace while King Sejong ( played by Han Suk-kyu , in his TV comeback after 16 years of solely film work ) comes to create the Korean written language . 
<triplet> Korean written language <subj> King Sejong <obj> creator