Missing Crown Prince

A group of rebels invades the palace, but the Crown Prince is nowhere to be seen. When the King finds out that he was outside without reporting to him, he and Queen Dowager decide to marry him off so he'd behave better. One day, a young court maid is found dead in a pond. She turns out to be a court maid of the Queen Dowager's chamber. The Crown Prince sneaks into the Queen Dowager's chamber to find out what happened in more detail, only to witness a hidden affair. 

Royal Physician Choi kidnaps a young man to use him to get rid of Myung Woon's misfortune. However, the young man turns out to be the Crown Prince. Myung Woon secretly saves the Crown Prince and takes him back to the palace safely. Meanwhile, the Queen Dowager demands the King to give up on the Crown Prince, saying he could lose his throne if he doesn't.

The Crown Prince makes it out of the palace with Gap Seok's help, and they meet Myung Yoon, who is waiting outside the palace. Myung Yoon helps to heal the prince's stab wound. The King orders Prince Dosung to find out the owner of the needle canister. Meanwhile, Physician Heo Jin Soo is found dead in his house. 

Prince Dosung discovers that his grandfather, the Left State Councillor, joined hands with the Queen Dowager and gets infuriated. The Crown Prince meets Prince Dosung secretly and tells him about Queen Dowager's secret affair and who her secret lover is. Meanwhile, Queen Dowager meets the Queen and asks for her help dealing with the King.

The King falls gravely ill after having a meal with a poisoned yellow croaker. The Crown Prince is arrested for providing the poisoned fish and put behind bars. Myung Yoon sees the Crown Prince being taken away, so she goes to Prince Dosung to ask why. Meanwhile, the Left State Councillor and the Queen Dowager carry out their plan to replace the Crown Prince with Prince Dosung in earnest. 

Prince Dosung uses Magistrate Yoon to help the Crown Prince escape the prison. The Queen Dowager announces that she will install Prince Dosung as Crown Prince and proceed with the wedding preparation for him and the prospective Crown Princess. However, the royal seal goes missing, putting a stop to everything they planned.

Myung Yoon decides to stay with the Crown Prince until he safely makes it out of the Capital. But Myung Yoon suddenly falls ill, which forces them to visit a nearby physician. However, the physician notices who they are and calls the government officials to catch them. Meanwhile, the Left State Council suggests forging the royal seal to install Prince Dosung as Crown Prince. 

When Prince Dosung finds out about the plan to forge the royal seal to install him as Crown Prince, he causes a scene at the palace by performing an exorcism. The Queen Dowager gets swayed by the aftermath of her plan. Gun and Myung Yoon barely escape from the government officials and make it to Gun's grandfather's house. There, Myung Yoon finds out who Gun really is. 

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.

The Queen Dowager and Choi Sang Rok fail to leave the palace. Choi decides to kill the Crown Prince as a last resort to keep both the Queen Dowager and Myung Yoon safe. However, his plan fails as Myung Yoon stops him. Meanwhile, the Queen visits the royal taster in her cell and tells her to kill herself.

Myung Yoon finds out about the affair her father has been having with the Queen Dowager and is shocked. Gun and Dosung convince Myung Yoon to leave the capital as she could be in danger, but she insists on staying at her place as she can't abandon her father. Frustrated by Myung Yoon's decision, Moo Baek tells her what her father did to her deceased mother.

Gun suggests dismissing a certain number of court ladies as a way to appease the sky and improve the King's health. The Queen, who holds the power to manage the court ladies, decides to dismiss Court Lady Kim of the Queen Dowager's chamber. Meanwhile, Gap Seok confesses to the court that the Queen was behind the death of the royal taster.

After finding out that his grandfather injured Myung Yoon while trying to get her out of the palace, Gun gets infuriated and asks him to go back to Mungyeong. While the Queen Dowager is away from her chambers, Myung Yoon manages to sneak out the book that contains a prescription for the antidote. Meanwhile, Prince Dosung joins hands with the Queen Dowager and declares that he will become the Crown Prince. 

Gun's grandfather, Jang Hyun Mok, gets tortured under the Queen Dowager's order, and Gun can't do anything to stop it. Myung Yoon steps up and asks the Queen Dowager and her father not to kill Jang Hyun Mok and that she will marry Prince Dosung in exchange. The Queen Dowager announces that Prince Dosung will be installed as Crown Prince and Gun will be dismissed from the palace. 

The King wakes up and meets Gun. Together, they mobilize the Tiger Hunters to take over the palace and bring down the Queen Dowager. The Queen Dowager also makes a move and lets the Tiger Hunters in the palace to protect themselves against Left State Councillor Yoon. Meanwhile, Left State Councillor Yoon secretly orders Court Lady Cho to kill the King. 

The King puts everything back in order. He dismisses every subject who was involved in overthrowing him. Gun gains his title as Crown Prince again, and Prince Dosung is removed to a private residence. Choi Sang Rok gets confined, but he decides to run away with the Queen Dowager. 

Choi Sang Rok finds out that the Queen Dowager is pregnant with his child. He suggests returning to the palace so the Queen Dowager and the baby can be safe. Choi Sang Rok realises that Myung Yoon helped the King gain consciousness. Master Geowoo visits Myung Yoon to explain what happened on the night her mother got killed. Meanwhile, Choi Sang Rok plans a coup with Yoon Yi Kyum and Yoon Jung Dae. 

Choi Sang Rok gathers the Seoin Faction and Dosung to carry out a coup. Yoon Yi Kyum kidnaps Myung Yoon to have Dosung on his side. Gun gives an order to depose Queen Yoon and kick Prince Dosung out of the palace. The vassals insist on Gun getting married quickly to have an heir, but he doesn't seem satisfied with any bride candidates.