The fifth episode of Moon River commences with Yi Kang and Dal-i plummeting into the water beneath the bridge, their fates intertwining once again. As dawn breaks, they awaken in each other's bodies, their shock palpable. (In this recap, Yi Kang refers to the genuine Yi Kang within Dal-i's body, while Dal-i speaks of the actual Dal-i in Yi Kang's body.)
Yi Kang attempts to impart the body swap to Je-woon, but his words fall on deaf ears. At the palace, Dal-i urges Se-dol and Shin-wan to locate Dal-i (in her own body) and escort her to the palace, unaware that her casual mention of Dal-i will swiftly reach Minister Han-chul's ears. Se-dol and Shin-wan inform her of the minister's threat to eliminate Dal-i upon discovering she bears the crown princess's features.
Meanwhile, Han-chul instructs Woo-hee to attend the palace as "bissi" – one of the women eligible for the royal selection as Yi Kang's wife, set to take place in two days.
In the town, Yi Kang endeavors to speak with Cha Eun-woo for access to the palace, but he is rebuffed. When he attempts to hide in a cart bound for the palace, Yi Kang is escorted to see the Dowager Queen Han. He proposes using Dal-i's resemblance to the crown princess to sway Yi Kang and halt his marriage with Han-chul's daughter. The queen is impressed and agrees, but given her potential exposure as a court lady, they decide upon a more discreet plan: sending Yi Kang in the guise of a eunuch.
Thus, Yi Kang presents himself as eunuch Lee Gang-dol and finally meets Dal-i. With Dal-i's behavior growing increasingly erratic, the king had ordered his son's confinement. Yi Kang's first order of business is to petition the dowager queen to lift the confinement on her son's behalf.
The queen concocts a plan, ordering a soothing bath for Yi Kang, hoping to ignite the sparks between him and "Dal-i" within the confines of the chamber. As they bathe together, Yi Kang suggests recreating the moment that brought them closer - the kiss. Dal-i acquiesces, and their lips meet once more, but the magic eludes them. Frustrated, Dal-i playfully dips Yi Kang beneath the water and kisses him again, only to find that it only provokes panic in him.
Back in the prince's quarters, Dal-i muses aloud if they must leap from the bridge to rekindle their connection. The next day, they enlist Cha Eun-woo to distract the guards, seizing the opportunity to venture to the bridge. Dal-i reveals Yi Kang's fear of water and promises to shield him, urging him to close his eyes. Even this act fails to yield the desired effect.
In a bid to salvage the situation, Yi Kang proposes a bold plan: Dal-i must temporarily pretend to be him. He imparts instructions on how to do so, but Dal-i tends to do the exact opposite, even going so far as to join in the king's meals.
Meanwhile, Hong-nan frets over Dal-i's predicament. A flashback reveals her love for the crown princess's brother, who was falsely accused of attempting to assassinate the late queen.
In the palace, gossip begins to swirl about the new eunuch's striking resemblance to the crown princess. The news reaches Woo-hee, who convenes a meeting with Yi Kang. She reveals her intention to use Dal-i's likeness to sway the crown prince's heart.
The next day, Yi Kang is forced to endure the eunuch's rigorous exercises, which he himself had ordered. In the process, Han-chul nearly uncovers his true identity, but Se-dol swiftly shrouds him in a bag of flour to ensure the minister doesn't recognize the resemblance to Dal-i.
That night, as Dal-i sleeps, she experiences Yi Kang's tormented dreams. Realizing what has happened, Yi Kang takes her on a midnight stroll and apologizes for his harsh words from the previous episode. They discuss dreams, with Dal-i confessing her longing for a life of leisure and comfort - a life of someone who wears flower shows. In response, Yi Kang leads her to a courtyard and shakes the branches of a tree, creating a path of blossoms for her. Touched by his gesture, as they draw closer, Yi Kang leans in for a kiss.
The episode concludes with them waking up in each other's arms, surrounded by the stunned gaze of the entire palace staff.
