In Episode 10 of "Perfect Crown," Hui-ju begs her father to save Prince Yi-an as she returns to the palace to request a divorce from her husband. Prince Yi-an is taken aback by her sudden request, and she tears his heart apart by claiming that he has nothing left to offer her. She insists that she must leave to save her father's company and the remaining part of her inheritance. She reminds him of his promise not to bind her to him. He begs her to reconsider, but she continues relentlessly.
A heartbroken Prince Yi-an retreats to the late king's chambers to wallow in his sorrow. He recalls calling his brother weak for not being there for Yi-rang when she was all he had. At the time, the king claimed that Yi-rang never relied on him. Looking back, he now understands the helplessness that comes with the throne and how his brother must have felt.
The next morning, Hui-ju comes to the office to check if Prince Yi-an spent the night there. She asks for his permission to attend the meeting at the council hall so she can ask for a divorce. He agrees. Outside, Hye-jung and Chi-hyun wonder if the couple will get a divorce. Choi-hyun fails to mention that Hui-ju is doing this to protect Prince Yi-an. Hye-jung receives a call from the prince and leaves.
At the meeting, Hui-ju acts confidently, taking all the blame and collaborating with the Castlegroup team to change the narrative. Tae-joo shines in the spotlight as he holds a press conference, defending Hui-ju and Prince Yi-an. He reveals that he wrote the marriage contract and points out that it was not notarized by a lawyer, meaning all parties ultimately lose in the event of a divorce. Lastly, he warns the fake news media that he plans to sue them for defamation.
Meanwhile, Hui-ju insists that she will take all the blame and asks Jeong-woo to investigate her once her royal titles are stripped. She promises that Prince Yi-an will be found innocent and will not step down from his regency.
Sung-won's nerves start to fray as Prince Yi-an remains silent about his agreement to the divorce. Just then, the royal secretariat enters the room and asks Prince Yi-an to prepare for the king's orders. It turns out that Prince Yi-an had earlier met with Yi-yoon and asked him to return his throne. Yi-yoon voluntarily abdicated and named Prince Yi-an as his successor. Sung-won tries to question the legitimacy, but Prince Yi-an asks him where he gets the audacity to do that. According to the rule, Prince Yi-an declines the request, as he is expected to do it three times before accepting it. The meeting ends, and Hui-ju chases after Prince Yi-an to explain. She accuses him of not trusting her enough to protect them and walks away.
On the other end of the palace, Yi-rang nearly loses her mind when she hears the news of Yi-yoon's abdication. She rushes to meet him, but the young king has locked himself in his room. She threatens Court Lady Im to break the doors or start a fire. Jeng-woo intervenes and asks her to stop taking the matter too far. In her office, he threatens her with the poisoning case and orders her to either get the prince or the king in line before he ruins her family's reputation. He wants her to handle everything before the third request.
Meanwhile, Prince Yi-an goes on a ride and ignores Hui-ju's calls. Hye-jung lies to her that she is going to find Prince Yi-an, but she already knows where he is. He is staying at his private residence to avoid getting Hui-ju wrapped up in more chaos. This is what he told Hye-jung when he called her.
Hye-jung grabs Choi-hyun and takes him drinking at the Han River. She confesses that she likes that kind of unwinding. He responds by saying he likes it too, and she asks whether he likes the beer, the view or her. He blushingly admits he likes everything.
Prince Yi-an goes to a rooftop to contemplate his relationship with Hui-ju. She keeps texting him, and finally, Court Lady Jin-sook has had enough of seeing Hui-ju moping around worried like a mother hen. She suggests that she go to the prince before the palace gates close.
Hui-ju texts Prince Yi-an, saying that she is sick, and he responds by saying that he will be back the next day. She goes to his private residence and confesses her feelings. She kisses him and asks if he no longer wants her. He kisses her back passionately, and they end up spending the night together.
The following morning, Prince Yi-an confides in Hui-ju that he is scared to become a king. He knew about the king's last wish and still allowed Yi-hoon to take the throne. Before dying, the king had made a Gonryongpo for Prince Yi-an. Unfortunately, he got it the night his brother died and felt that he was too late to help him. Now he wants to protect his nephew, but he is not sure if he is also being greedy. She assures him that there is nothing wrong with being greedy, and she agrees to stay by his side.
They return to the palace, where Yi-rang seeks an audience with Prince Yi-an. She begs him to refuse the throne, but he insists that he will no longer remain silent and will protect his young nephew. He mentions that she should be thankful that Yi-yoon abdicated willingly and that he won’t make her pay for her sins.
Yi-rang demands to know why he is now coming for the throne, bringing up their past. It turns out that she had dreams of being a pianist and that her first love was Prince Yi-an. Her father forced her to give up everything and become the crown princess. She figures that Prince Yi-an should also sacrifice the throne. He pulls her off him and orders Court Lady Im to prevent anyone from seeing Yi-rang for the next three days.
She calls her father to tell him it’s over, but he refuses to accept defeat. Instead, he says he has a plan but refuses to share it with her. That night, Jeong-woo visits Sung-won. On the day of the last edict, Prince Yi-an’s team gets him ready. Hui-ju proudly encourages him and promises to wait for him in his palace quarters.
Meanwhile, Yi-hoon reveals to Yi-rang that he heard his father’s last wish the night he died. She is heartbroken to realize he knew everything all along, even when she forced him to take the throne and ordered him not to disappoint her, as he was her last hope. He tearfully apologizes for disappointing her.
She tries to call Prince Yi-an, but he ignores her calls. Yi-rang summons Court Lady Im and asks her to bring forth the court lady she hid in the palace. Elsewhere, Jeong-woo stalls for time before heading to the council hall. While worrying about whether the public will accept her as their queen, Hui-ju gets a call from Tae-joo asking what is next in their plans. She opts to meet in person and gets ready to leave. On the way, she runs into Sung-won.
Meanwhile, Prince Yi-an gets a text from Jeong-woo asking to meet at the council hall before heading to the throne hall. The next thing we know is that a bomb goes off in the council hall. Hui-ju, who was still in the palace, rushes to see what is happening. A shocked Hye-jung confirms her worst fear by revealing that Prince Yi-an was inside the building. The worst part is how proud of himself Sung-won looks.
