An immortal emperor rules the Kingdom of Yeol, a divine country blessed by gods with awesome powers. After a thousand years of peaceful rule, the time has come for a new emperor to be chosen. This is determined by a series of trials, in which twenty princes with special powers who have trained since birth must compete. As all princes of varying personalities and agendas gather to partake in the trials, intrigue and possibly even bloodshed seem all but certain. Meanwhile, unbeknownst to the other princes, the Fourth Prince Jeok-yeon Ryu hides a secret he must guard with his life.