조선의 3대 왕이자 조선 500년 역사의 기틀을 세운 인물, 태종 이방원을 새롭게 조명한다. 이성계의 다섯째 아들인 방원은 힘든 삶을 사는 백성들을 위해 새로운 세상을 열 야망을 키워간다. 이성계가 고려를 정리하고 새로운 나라를 세우는 과정에서, 방원은 충신 정몽주를 제거하는 등 그 누구보다 과감한 결단을 내리고 행동한다. 하지만 조선 건국 후, 그는 왕권을 놓고 형제뿐 아니라 아버지와도 갈등을 빚는다.
Lee Bang Won is the fifth son of General Lee Seong Gye, the founder of Joseon. He has lofty ideals and the power to make them happen. Lee Seong Gye is a great man who knows how to embrace people and see through the world. At the end of Goryeo, a dynasty on its deathbed, Lee Bang Won harbors an ambition to change the world for the people who struggle to survive. He helps his father and prepares for the great work with Jeong Do Jeon and many others. In the process, he kills Goryeo's loyal subject, Jeong Mong Ju. Lee Bang Won thus took the initiative in founding the new dynasty, destroying the old regime of Goryeo, and establishing the new order of Joseon. The new world is established, and Lee Bang Won is about to clash with Lee Seong Gye over the royal power. Will the son move in a new direction?