The King falls into a critical condition, and Choi Sang Rok is the only one who knows how to cure his illness. Prince Dosung decides to comply with Queen Dowager's order in exchange for saving his father and the Crown Prince. After finding out who Gun is, Myung Yoon reveals her identity as well. Meanwhile, Choi Sang Rok finds leverage he can use against Left State Councillor Yoon.

The Queen Dowager is infuriated by the attack Left State Councillor Yoon launched on her. Upon hearing the news, Prince Dosung begs for her forgiveness, and he is told to convince his grandfather to resign and retire to the countryside. Meanwhile, Myung Yoon enters the palace upon her father's order. Prince Dosung asks for Myung Yoon's help in finding the poison used on the King.

On the day of Prince Dosung's investiture ceremony, Gun shows up with the real royal seal. He clears his name in front of everyone and finds his place in the palace again. Gun warns the Queen Dowager and Choi Sang Rok that he will carry out an interrogation to disclose who poisoned the King. Choi Sang Rok comes up with a way to save both the Queen Dowager and himself.