The tenth episode of Moon River commences with Han-chul's arrest, setting the stage for a subsequent twist as the king issues an order to terminate Dal-i's life. Meanwhile, the masked figure ventures into a seedy part of town, a den for ruthless warriors. Her attempts to rally them are met with resistance from their leader, who insists on "His Excellency's" permission before taking action.
In the palace, Yi Kang and Dal-i negotiate with Jo Mi-geum, who agrees to work with them only if they promise to save her lover, the former chief secretary. Yi Kang relents reluctantly. However, a shocking turn of events unfolds as the king himself releases Han-chul from jail, allowing him to return to the palace undeterred. He swiftly learns of Woo-hee's escape and sends search parties in pursuit.
In the palace, Dal-i continues to plagued by dreams of the crown princess. The following morning, Yi Kang receives an unexpected call from the king, prompting him to visit the monarch's chambers. There, he is stunned to see Han-chul freely roaming about as if nothing had happened.
A flashback transports us back to the Gyesa Year incident. After the previous king and his son meet their fate, Han-chul pays a visit to Yi Hui (now the king), who was a prince at that time. Han-chul reveals that he killed them all and has hidden the poison in Yi Hui's quarters, offering him a choice: either become the traitor or ascend the throne and support Han-chul. Yi Hui chooses the latter and signs a pact admitting his role in a coup to seize power from his brother. Over the years, Han-chul has used this pact as blackmail to manipulate the king into doing his bidding, ultimately leading to the deaths of the queen and crown princess as he dismantles the king's supporters and uses him as a puppet monarch.
Presently, Yi Hui reveals the entire truth to Yi Kang and implores him to survive, even if it means being a coward. Elsewhere, the grand dowager queen learns of Woo-hee's escape and confirms the truth for herself. She urges Yi Hui to cancel the royal wedding once and for all, but he resists.
As Woo-hee and Je-woon awaited the arrival of a boat, they found themselves suddenly surrounded by Han-chul and his heavily armed retinue. Je-woon valiantly fought back, but his efforts were ultimately futile against the overwhelming numbers. Yi Kang's arrival brought a measure of relief, but not before he informed them that the palace already knew of Woo-hee's elopement. Instead of punishing her for her daring act, Yi Kang proposed a peculiar solution: allowing the couple to leave unhindered and find happiness. However, Han-chul pondered whether it would be best to eliminate Woo-hee altogether, thus eliminating any evidence of her elopement in the first place. Je-woon offered to take his own life in her stead, but Woo-hee intervened, agreeing to return to the palace on her own and calling for a temporary truce among all parties involved.
While Yi Kang filled Je-woon in on the developments, Woo-hee turned to her father and asked him why he coveted the position of father-in-law so much. He revealed that it would give him power over even the king itself. From that moment on, he confined Woo-hee to her quarters. Meanwhile, Dal-i comforted Yi Kang, assuring him that together they would find a way out of their predicament.
During the next council meeting, the ministers urged Yi Kang to proceed with the royal marriage as soon as possible. Later, Han-chul and his two co-conspirators discussed the sighting of Hong-nan in Hanyang, prompting Han-chul to order his men to investigate further.
The dowager queen soon realized that the left minister had some leverage over Yi Hui and Yi Kang. She encouraged Yi Kang not to be held back by fear and went with Dal-i's words to approach the king with a bold proposition. He suggested they relinquish the throne to Je-woon and prove that the pact with Han-chul was made under duress, thus taking down the left minister. However, the king appeared unpersuaded.
Later, the king met with Hong-nan and asked her if Dal-i was truly the crown princess. Hong-nan admitted the truth, revealing that the king had sent her a letter telling her to flee just a day before he poisoned her. Despite this, she chose to attempt suicide, which resulted in her losing her memory. Now, she asked the king to save the princess this time.
Hong-nan then returned to Dal-i's parents and informed them that they would be traveling together to Qing with Dal-i as well. She disclosed the truth about Dal-i's identity to them.
In the palace, the king revealed his plan to make separate arrangements for Dal-i's family's residence and sent her to visit them. The scene then returned us to the beginning of the episode, but this time it was clear that the king was asking his men to fake Dal-i's death so she could escape unnoticed.
As Dal-i moved into the new residence arranged by the king, a palace staff member remarked on how much she resembled the crown princess. The only difference, she pointed out, was that Dal-i did not have a mole on her nose—a detail Hong-nan had instructed her to cover up. When Dal-i's handmaiden caught a falling petal, Dal-i joked that she would get her first love. This innocent remark triggered a flood of memories from her past in the same residence, and suddenly, Dal-i knew who she truly was. The episode ended with Dal-i asking Hong-nan why she had lied to her all along.
