The story takes place at a time in Joseon history, when upheaval and power struggles surrounding the throne had reached extreme levels. In order to escape those who plan to assassinate him, the king puts a clown, who looks exactly like him, on the throne.
Anxious about the traitors out there and haunted by the ghost of the brother he killed, Heon can never sleep in peace. He desperately asks the Chief Royal Secretary, Lee Kyu, to find a way to eliminate his fears. Like what the Monkey’s hair does in “Journey to the West”, a doppelganger of Heon appears before his eyes
As soon as Heon sees Ha Seon, he leaves the palace right away. Eunuch Cho and Lee Kyu try to train Ha Seon to perform a perfect double of the King. Ha Seon gradually realizes that he is needed in the palace to die instead of the king. To frightened Ha Seon, Kyu advises the ways to survive in the palace.
Ha Seon returns to the palace to find the way to take his revenge on Shin Yi Gyum and those who give him power. Meanwhile, those who are after the King push ahead with the hunt to use this as a chance to kill the King. Lee Kyu and Eunuch Cho are worried that Ha Seon might get caught that he’s a disguise.
Seon Hwa Dang falls ill after drinking tea with the Queen. This poisoning incident gets out of the Queen’s hands. Ha Seon tries his best to find the way to save his queen as he promised. Meanwhile, Shin Chi Soo carries out his plan to dethrone the Queen and the Queen Dowager.
To solve the taxation issue, Lee Kyu and Ha Seon try to persuade Joo Ho Geol, who is known to be a calculation genius, to join them. Meanwhile, seeing how Ha Seon thinks to put the people before anything revives the dream Lee Kyu once had. With Woon Shim, Lee Kyu meets with Lord Gil’s followers.
Despite the sweet words of the Queen, Ha Seon feels heartbroken as he knows her feelings are towards the real king, not him. Meanwhile, Lord Shin and his son, who were scheming against the investigation on tax embezzlement, in turn face some unexpected humiliation.
With Dal Rae’s help, Heon escapes the temple and returns to the palace. He becomes furious to see how the Queen has changed and how his servants treat Ha Seon. To make sure his servants stay loyal, Heon orders Ha Seon to be killed and decides to spend a night with the Queen as soon as possible.
Officer Jang finds out Ha Seon was not dead and reports it to Lee Kyu and Eunuch Cho. Meanwhile, Heon feels betrayed by the Queen and orders her to be deposed after failing to spend the night with her. When he collapses, Lee Kyu orders Officer Jang to take him away somewhere safe while Ha Seon gets ready to return to the palace as the real king.
After being demoted, Lord Shin visits Lord Jinpyeong to suggest his plans. Lord Shin also becomes suspicious about Ha Seon’s identity and orders posters of Ha Seon’s face be put up in the marketplace. Meanwhile, Ha Seon cannot hide his feelings for the Queen any longer, and confesses his love for her.
Lee Kyu is surprised to find out how close the Queen and Ha Seon have become. He tells Ha Seon to give up on his personal feelings to become the real king. Not knowing what’s on the King’s mind, So Woon decides to write a reply to Ha Seon’s love letter.
Shocked to find out whom she has loved so far, So Woon decides to leave the palace. Ha Seon refuses to agree to deposing the Queen. Meanwhile, Lord Shin and Lord Jinpyeong seek to take advantage of the disorder in the palace.
To check on the people, Ha Seon decides to visit the marketplace with the Queen. Dal Rae and Gab Soo hear from Ho Geol that the King looks exactly like the man in the poster and that he will visit the marketplace. While Ha Seon is talking to the people, Shin Yi Gyum is suddenly attacked and the attacker is taken to prison.
Between the two ways to survive in the palace, Ha Seon who has become the King and has the king’s authorities chooses to trample on his enemies. To save those that he holds dear, he goes against the enemies one by one.
After Ha Seon finds out about Lord Yoo’s death, he and Lee Kyu make the Queen Dowager confess her crimes in order to depose her. In the process, Ha Seon speaks with Shin Chi Soo and hears that Lee Kyu killed Heon. Will Ha Seon become suspicious of Lee Kyu and side with Shin Chi Soo?
To face the rebel forces head-on, Ha Seon orders them to come into the palace with Lee Kyu for a morning assembly. While Lee Kyu is locked up in a cell, Shin Chi Soo tries to talk him into persuading the King to give up the throne.
With Lee Kyu’s sacrifice, Ha Seon successfully punishes those that tried to kill him. After he suppresses the rebels, like the sun, he takes care of his subjects and the people. When he decides to abdicate and leave the palace, he promises the Queen to meet her in a small village.
