In the twelfth episode of Moon River, the reunion between Yi Kang and Dal-i is followed by a profound conversation about her past, with her urging him to treat her as he did Dal-i. She dares him to choose between her and Yeon-wol, but he deftly avoids the question, leaving her hanging in the balance of his loyalty.
Meanwhile, in Wolha's garden, a sinister red light illuminates the blossom symbolizing Yi Kang and Dal-i, as Wolha observes that Han-chul is turning into a monster due to his inability to let go of the past. At the palace, Han-chul realizes the truth about Dal-i's identity and Hong-nan's scheme, leading him to arrest Dal-i's adoptive parents and Hong-nan.
Dal-i struggles to recall her memories, one of which is hazy - meeting Han-chul at her mother's grave on Gamksan Mountain. She suspects she witnessed something she shouldn't have. A letter arrives, revealing that Han-chul has her family, and she arrives just in time to stop the execution. In a desperate bid to save them, she is forced to reveal her true identity to Han-chul.
Once everyone knows she's the formerly deposed crown princess, Han-chul takes the opportunity to arrest her. Yi Kang goes to the king for help but is met with a claim of helplessness, forcing him to sentence her to death by strangulation.
In prison, Dal-i decides to play a game of deception, pretending her memories are intact. She tells Han-chul she knows his secret at Gamaksan Mountain and that Yi Kang will reveal it if he kills her.
Je-woon comes to see Yi Kang and learns on the way that Woo-hee has asked for her wedding robes. Yi Kang soon receives the robes from Woo-hee, hidden inside a note outlining a plan - she will escape her confinement and distract her father so Yi Kang can help Dal-i escape.
That night, Woo-hee takes one of her ladies in waiting hostage and escapes the palace in the maid's clothes. Je-woon meets her outside and they run away, with the news soon reaching Han-chul. He goes to the prison only to discover the truth - the woman inside isn't Dal-i, it's Woo-hee. Woo-hee took her place and let Dal-i escape, leaving behind a trail of deception and intrigue in this complex web of power and love.
As the moonlight filtered through the intricate patterns of the palace roof, Dal-i and Yi Kang crept out, concealed within the cart of royal silk that Yi Kang had earlier ordered to be returned to the merchants. In the shadows, Je-woon found himself surrounded by Han-chul's men, but with a quick maneuver, he escaped, leaving behind a bound woman whose hands were a testament to her captivity—Woo-hee's maid.
A memory of Yi Kang recounting Han-chul's army of the nameless ones to the king lingered in their escape. Yi Kang believed that the leader of this enigmatic force held the secret pact and aimed to find it in the mountains, with Je-woon's assistance. It was at this moment that Yi Hui urged them to flee the palace, entrusting Yi Kang with the hobu—one half of a wooden tally imbued with royal power to rally troops.
Meanwhile, Woo-hee's words echoed in Je-woon's mind as she urged him to ride away with her maid. He hugged her tightly, and she whispered in his ear, promising to see him again if he survived. In the present, Han-chul confronted his daughter and killed her handmaiden, Yeo-ri, as punishment.
Without hesitation, Han-chul issued a call for the capture of Yi Kang and Dal-i. The two fugitives saw the nameless ones closing in on them and took refuge in the humble abode of an old man whose life Dal-i had once saved. There, she revealed to Yi Kang her memories from Gamaksan Mountain.
A flashback showed Yeon-wol visiting her grave when a woman in white mourning clothes rushed towards her, begging for help. A nameless one intervened, explaining that she was confused due to recently losing her son. He took her back, and Yeon-wol noticed her feet were clean, suggesting she hadn't walked a long way—a clue that the nameless ones had a base at Gamaksan Mountain.
Furthermore, Yeon-wol's brother had been investigating the incident. Before her deposition, he gave her a book and asked her to give it to the king in case anything happened to him. Yi Kang now remembered a similar book stored with Dal-i's belongings back at the palace. They spent the night at the old man's house, their conversation lingering in the air as they considered running away and living as ordinary people. Dal-i simply smiled and held his hand, her eyes filled with a mix of determination and hope.
Returning to the palace, the Dowager Queen learns of Woo-hee and Je-woon's ill-fated attempt at elopement. She shares this information with Han-chul, urging him not to allow Je-woon to ascend the throne in exchange for her silence. Han-chul is enraged upon learning that the Dowager Queen insults Queen Jangjeon, blaming her and Je-woon for the deaths of her son and another grandson. In a flashback, we see that the woman tending to Han-chul's wounds as a young boy is none other than Queen Jangjeon herself.
Meanwhile, Yi Kang hires a boatman to prepare a vessel for their escape to Qing, accompanied by Dal-i. Unfortunately, the boatman spots their arrest warrant flyer and raises the alarm. As Yi Kang and Dal-i are joined by Shin-won, who desires to assist them, they go to see the boatman together. However, all three of them are soon surrounded by Han-chul's men. Yi Kang threatens to kill himself, forcing the men to let Shin-won and Dal-i leave unscathed. Yet, we learn that Yi Kang and Dal-i have once again swapped bodies.
In a flashback, we see Dal-i telling Yi Kang that instead of running away, they should fight for those they love and cling to any remaining hope. They devise a plan and decide to use the body swap to their advantage. As Yi Kang can fight, he goes to the mountain in Dal-i's body, while she returns to the palace to search for her brother's book.
In the present, Dal-i returns to the palace but is confined to Yi Kang's quarters. She gives Se-dol a coded message, through which he finds her brother's book, "The Art of War," and delivers it to Je-woon. Along with the hobu, Dal-i sends a message of hope and determination.
In the book, Je-woon finds coordinates to the Nameless Ones' hideout in the mountain and goes there with Yi Kang and Shin-won. There, they discover that Queen Jangjeon is still alive! More flashbacks reveal the relationship between her and Han-chul when they were young, with a short clip showing him asking her to marry him after passing his military exam.
In the present, Han-chul puts on shoes for Queen Jangjeon, revealing her mental disorder and her apparent living in the past. As Yi Kang, Shin-won, and Je-woon sneak into the Nameless Ones' camp, the latter sees his mother and recognizes her. The tension and emotions of this moment are palpable as they confront each other in this unexpected encounter.
