이강에는 달이 흐른다
Sarcastic Warning: Contains Maximum Tropes. Oh look, a prince obsessed with revenge meets a commoner who looks EXACTLY like his dead wife - it's the classic drama bingo! Naturally, they switch bodies because why not? Prepare for royal shenanigans and identity crises galore.
Heo Yeong Gam's daughter is forced by her in-laws to take her own life over a matter of loyalty, prompting her neighbor Park Dal I to travel to Hanyang to save her. This family crisis is the inciting incident that brings Dal I into contact with Crown Prince Yi Gang, setting the entire series' plot into motion.
Crown Prince Yi Gang appears wild, unruly, and pleasure-seeking, but privately hides deep grief after losing his beloved Crown Princess to a palace power struggle. He becomes the reluctant heir who pretends carelessness to survive court politics, silently enduring the weight of his position while planning revenge. Everything changes when he encounters Park Dal I, a woman who looks exactly like his deceased wife, and the two mysteriously swap bodies, pulling him into a chaotic path toward truth and healing.
Yi Un is a Grand Prince and the only legitimate son of the late Emperor and Queen Jang Jeong, whose execution on false charges drives much of the story's underlying conspiracy. Subdued and quick-witted, he carries a complicated past and a layered emotional arc involving romantic feelings for Kim U Hui, who is instead forced to marry Crown Prince Yi Gang. His storyline intertwines court politics, forbidden love, and quiet resentment toward the forces that shaped his fate.
Yi Hui is the reigning King of Joseon and Crown Prince Yi Gang's father, though in practice he is a puppet ruler manipulated by Left State Councillor Kim Han Cheol. His powerless position anchors the central conflict of the drama in palace politics, illustrating the extent of Kim Han Cheol's control over the throne.
O Sin Won serves as the Left Commander of Ikwisa and is a loyal friend and warrior to Crown Prince Yi Gang. His unwavering support highlights the strong bonds of friendship within the prince's inner circle amid the palace's political dangers.
Yun Se Dol is Crown Prince Yi Gang's personal eunuch, having grown up alongside him since childhood out of genuine loyalty. He claims he became a eunuch purely out of devotion to Yi Gang, but this is not entirely true, and he tends to reveal the real, more embarrassing story of how it happened when drunk, adding comic relief to his close bond with the prince.
Heo Yeong Gam was once a fierce general who ruled the seas but is now completely disarmed by devotion to his precious daughter, born when he was over fifty. He lives solely for her, willing to set aside his pride and even weep openly on her behalf. His daughter's crisis, being forced by her in-laws to take her own life, is what draws Park Dal I into the capital at the story's start.
Kim Ja Gyeong is the Minister of Personnel, a close ally and distant relative (fifth cousin) of Left State Councillor Kim Han Cheol. He is greedy but lacks political insight, often irritating the Councillor despite their family and political ties.
Cha Eun U is an apprentice with the Hanyang merchant guild who serves in a role akin to Crown Prince Yi Gang's personal stylist. Despite his impressive-sounding name, his looks are described as falling short of expectations, giving him an unexpected, self-deprecating charm within the prince's circle.
Kim Han Cheol holds Crown Prince Yi Gang and the entire royal family hostage to his political will, having murdered the previous king and installed a puppet ruler. Yi Gang's carefree public persona masks his quiet plotting for revenge against the Left State Councillor who destroyed his family's power and happiness.
PoliticalKim Han Cheol effectively controls King Yi Hui as a puppet ruler, having engineered his rise to the throne and holding real power over the kingdom in his place. This dynamic underlies the show's central palace conspiracy.
PoliticalQueen Dowager Han and Left State Councillor Kim Han Cheol represent opposing political factions, the Han family and the Kim clan, locked in a struggle for control over the throne. Her efforts to reclaim power for her family directly threaten his dominance over the King and royal court.
PoliticalKim U Hui is married to Crown Prince Yi Gang as the Crown Princess Consort, a union orchestrated entirely by her father for political gain rather than affection. Neither party entered the marriage by choice, and U Hui's true feelings remain with Grand Prince Yi Un, creating strain within the royal household.
RomanticKim Han Cheol is the father of Kim U Hui and forces her into a politically advantageous marriage with the Crown Prince against her wishes. Her repeated resistance to his plans strains their relationship and threatens to undermine his carefully built political power.
Family · ChangedYun Se Dol has served as Crown Prince Yi Gang's personal eunuch since childhood, and the two share a close, casual friendship rare between royalty and staff. Se Dol's loyalty and comic presence provide Yi Gang one of his few genuine, trusted bonds within the palace.
AllianceO Sin Won, Left Commander of Ikwisa, is a loyal friend and protector to Crown Prince Yi Gang, standing alongside Yun Se Dol as part of the prince's small trusted circle. Their friendship provides Yi Gang rare moments of levity and genuine camaraderie amid palace intrigue.
AlliancePark Hong Nan acts as a guardian and aunt-like figure to Park Dal I, offering warnings and holding secrets that set up early conflicts in Dal I's journey to Hanyang. Their close bond gives Dal I a source of protection and guidance despite her own memory loss.
FamilyPark Dal I travels to Hanyang specifically to help Heo Yeong Gam's daughter, her neighbor, who is being forced by her in-laws to take her own life. This act of loyalty sets the entire story in motion and reflects the close, caring bond between Dal I and Heo Yeong Gam's family.
AllianceDo Seung Ji serves as an advisor to Queen Dowager Han following the Gyesa Year Incident, working to help her reclaim political power for the Han family from the dominant Kim clan. Their alliance is a calculated partnership aimed at restoring the Han family's standing.
PoliticalKing Yi Hui is Crown Prince Yi Gang's father, though his own powerlessness under Kim Han Cheol's control limits his ability to protect or guide his son. Their relationship is shaped by the shared burden of living under the Left State Councillor's dominance.
FamilyPark Dal I is the daughter of a former eunuch whose forbidden love story with her mother nearly cost them both their lives. Their modest, loving household stands in sharp contrast to the palace intrigue Dal I is later drawn into.
FamilyPark Dal I is the daughter of a former court lady who once faced execution for falling in love with a eunuch. Her mother's quiet, grateful life after that ordeal shapes the humble household Dal I grew up in before her memory loss.
FamilyKim Ja Gyeong, Minister of Personnel, is a close ally and distant relative of Left State Councillor Kim Han Cheol, aligned with him politically despite lacking his insight and often irritating him with his greed.
PoliticalCha Eun U serves as an apprentice attached to Crown Prince Yi Gang's household through the Hanyang merchant guild, functioning informally as his stylist and aide.
ProfessionalThe Royal Palace is the seat of the Joseon monarchy, home to King Yi Hui, Crown Prince Yi Gang, and the royal family, and the center of the court intrigue orchestrated by Left State Councillor Kim Han Cheol. It hosts state weddings, political maneuvering, and the ongoing power struggle between the Kim and Han factions, and is where much of the show's soul-swap chaos unfolds as Yi Gang and Dal I navigate palace life in each other's bodies.
Hanyang is the capital city of Joseon, home to the Royal Palace and the bustling merchant world Park Dal I navigates before being drawn into royal affairs. It is where Dal I travels to save her neighbor Heo Yeong Gam's daughter, and where much of the series' central action, romance, and political conflict take place.
Boryeong is Park Dal I's home region, where she works as a peddler and lives with her parents and neighbors, including Heo Yeong Gam's family. Her strong local dialect and street-smart upbringing there mark her as an outsider once she enters royal circles in Hanyang.
The Hanyang Merchant Guild is a trading organization within the capital where Cha Eun U serves as an apprentice, connecting the common merchant world with the royal household through his attachment to Crown Prince Yi Gang. It represents the commercial backdrop against which Dal I's peddler background and the city's daily life play out.
The mountain villa is where a secret agreement tied to Kim Han Cheol's schemes is hidden, requiring Crown Prince Yi Gang and Kim U Hui to retrieve it and return to Hanyang before their state wedding. This location becomes a key setting for uncovering evidence of Han Cheol's crimes.
The Royal Court of Joseon is the seat of the kingdom's power, nominally headed by King Yi Hui but in practice controlled by Left State Councillor Kim Han Cheol. It is the center of the story's political conspiracy, palace intrigue, and the power struggle between the Kim clan, the Han family, and the royal bloodline itself.
Kim Han Cheol's faction is the dominant political bloc within the Joseon court, built on his position as Left State Councillor and his ruthless consolidation of power after murdering the previous king. The faction controls the throne through manipulation and fear, holding the King, Crown Prince, and royal family effectively hostage, and stands as the central obstacle to Crown Prince Yi Gang's plans for revenge.
The Han Family Faction, led by Queen Dowager Han and advised by Do Seung Ji, seeks to reclaim political power lost during the Gyesa Year Incident and challenge the dominance of the Kim clan. Its efforts to place loyal figures within the Crown Prince's household and manipulate palace succession drive much of the court's secret political maneuvering.
Park Dal I's family is a modest, quietly devoted household built on the forbidden love story between her father, a former eunuch, and her mother, a former court lady who narrowly escaped execution for their relationship. Their humble life in Boryeong stands in stark contrast to the palace intrigue Dal I is later drawn into after her memory loss and journey to Hanyang.
Heo Yeong Gam's household centers on the former general and his cherished daughter, whose crisis at the hands of her in-laws sets the entire story in motion. The household's troubles draw Park Dal I to Hanyang, linking this small family drama directly to the series' larger plot.
