In the sixth episode of Moon River, a masked figure launches an attack on Je-woon, revealing that he is the son of a Zhen bird merchant from Qing. Meanwhile, in a separate scene, Yi Kang and Dal-i share a romantic evening under the petals of falling spring blossoms. As seen in the previous episode, Yi Kang leans towards Dal-i, but it is only to shoo away a pesky bee, not to kiss her. That night, as they both sleep, Yi Kang pulls the blanket towards himself, and Dal-i follows suit, resulting in their inadvertent entanglement.
In the morning, Woo-hee stumbles upon Je-woon in the palace. He insists on addressing her formally and urges her to focus on marrying Yi Kang. Disregarding protocol, Woo-hee makes a beeline for Yi Kang's chambers and opens the doors to reveal Yi Kang and Dal-i asleep in each other's arms. Unfortunately, despite their efforts to spring apart, the scene itself hints at a forbidden intimacy. As Woo-hee had anticipated, Jo Mi-geum, the chief court lady's niece and a young woman, spreads rumors about what she saw. Je-woon, mistakenly believing that Woo-hee was the one who spread the rumors, threatens to set fire to the garden where they used to meet and tells her they should never see each other again. In her fury, she vows to overthrow the king and the prince and place Je-woon on the throne.
To keep them safe, Yi Kang flees the palace and heads back to Boryeong. While the king and left minister Han-chul embark on a search for the eunuch who dragged the prince into this scandal, Yi Kang goes into hiding with the help of Mr. Heo. Given that Dal-i saved his daughter's life, he agrees to assist in hiding Yi Kang.
Mr. Heo converses with Hong-nan, whose eyes widen in realization of the dire situation's gravity. She disburses some funds to Dal-i's adoptive parents, urging them to flee, claiming that she herself will depart the country with Dal-i. However, they resolutely refuse to relinquish their parental role, despite not being her biological parents. Instead, they insist on accompanying Hong-nan.
At the palace, Jo Mi-geum finds herself incarcerated for spreading the gossip. The chief court lady, her aunt, visits her in prison and reproaches her for her actions. She unveils her affection for the chief secretary, who was exiled for attempting to assassinate the king, and protests the injustice of the royals remaining unscathed. The chief court lady implores Han-chul for mercy and offers information on Dal-i's identity in exchange. Now aware that she resembles the crown princess, Han-chul uses this to boldly challenge the prince in front of the king.
Meanwhile, Yi Kang takes refuge at Je-woon's abode. Je-woon, unaware of the body swap, suggests that Dal-i marry him, thereby sparing her from being a fugitive and allowing the crown prince to focus on their vengeance. Yi Kang (speaking as Dal-i) declines the proposal.
Elsewhere, Han-chul enters a cave and we witness him tossing food towards the shadow of a bird. In Woo-hee's house, she catches a masked man searching for her gun and realizes that her father must have sent him.
As for the king, he addresses Dal-i (in Yi Kang's body) and advises her to surrender the eunuch to the left minister as their vengeance against Han-chul is of utmost importance. He promises to save Dal-i's life and allow her to live as a government slave.
Dal-i makes her way to Je-woon's abode, where she urges Yi Kang to surrender himself, offering the promise of a body swap and contentment in a life as a slave. But Yi Kang assures her that he has a plan to right the wrongs. Shortly thereafter, Shin-won finds Yi Kang and attempts to drag him back to the palace. Se-dol, however, intervenes, urging Yi Kang to seek the aid of the dowager queen instead.
Yi Kang eventually finds himself back in the palace, where he confronts the Minister of Personnel in front of the royals, accusing him of harassing Dal-i and forcing her to remove her clothes. Dal-i, now in Yi Kang's body, stands as a witness, and soon the ministers begin to turn on one another, exposing their own crimes.
Despite this, Han-chul persists in his demand for Dal-i to receive 100 lashes. Instead, Dal-i (in Yi Kang's body) asks the left minister to allow her to work as a government slave at Jeju Island. He agrees. But before Dal-i can finish giving the order, the Dowager Queen Han storms in, announcing that Dal-i is under her command.
A flashback shows Yi Kang (as Dal-i) ingesting the poison the queen used to try and kill the king. He presents it to the dowager queen not as a threat but as proof of his usefulness to her, convincing the queen to help him.
Once Yi Kang is safe, Dal-i attempts to cheer him up with a bubble blower, but as they try to convince the queen, Yi Kang tells her that the prince has a crush on Dal-i. He later tells Dal-i that he didn't mean it seriously, and Dal-i promises to help him with his revenge.
Elsewhere, Je-woon learns that it wasn't Woo-hee who spread the rumors. He immediately regrets his harsh words towards her. In the palace, the chief court lady informs Han-chul that Mr. Heo helped Dal-i's family escape. He claims that Dal-i is his wife's niece whose parents have passed away. A flashback shows Mr. Heo helping Han-chul and his family out of a scrap when he was younger. Han-chul tells the chief court lady to find Dal-i since he wants to check something.
The next day, Dal-i and Yi Kang spend their day in town. Yi Kang buys and puts on flower shoes, showing Dal-i how pretty she can look. They also get their portrait drawn. Suddenly, Yi Kang's mood shifts and he tells Dal-i to return to the palace. While Yi Kang is alone, masked men drug and kidnap him.
He wakes up tied to a chair, under the capture of the chief court lady, who is doing this on Han-chul's orders since he wants to check something. However, she also plans on making Yi Kang swallow a medicine that would render Dal-i infertile. As the chief court lady's women try to force the liquid down his throat, she pulls off Dal-i's flower shoes and throws them on the fire. This enrages Yi Kang, and he manages to fight back, breaking free from his ropes.
Still struggling from being drugged, Yi Kang makes his way out and sees the cave with the bird's shadow on his path. As he reaches the palace grounds, Dal-i eventually finds him and he collapses on her shoulder.
