Moon River

Also known as: Lee Gang, Lee Kang

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.

Also known as: Park Da-ohn (child), Yeon Wol

Park Dal I is a lively, witty peddler from Boryeong who lost her memories five years ago and now survives on sharp trading instincts and street smarts. She travels to Hanyang to help her neighbor, Heo Yeong Gam's daughter, and crosses paths with Crown Prince Yi Gang, whom she resembles closely. Through a mysterious body swap, she is drawn into royal secrets and eventually discovers she is the deposed Crown Princess, presumed dead, whose identity was buried along with her memories.

Also known as: Left State Minister, Left State Councillor

Kim Han Cheol is the Left State Councillor, a ruthless power broker who effectively rules as "the king above the king" through fiery ambition and cold calculation. He is responsible for murdering the late king and installing a puppet ruler, aiming to secure the throne for his own bloodline, and holds the King, Crown Prince, and royal family under his control for years. He is the father of Kim U Hui, whose repeated defiance of his plans threatens to undo his carefully built power.

Also known as: Kim Woo-Hee

Kim U Hui is the Crown Princess Consort and daughter of the powerful Left State Councillor Kim Han Cheol. She is secretly in love with Grand Prince Yi Un but is forced by her father into marrying Crown Prince Yi Gang instead. Smart and compassionate but trapped by her family's political ambitions, she repeatedly resists her father's plans, straining their relationship and complicating the palace's power struggles.

Also known as: Grand Queen Dowager

Queen Dowager Han was once the most powerful figure in Joseon before losing both her son and her power during the Gyesa Year Incident. She fears Grand Prince Yi Un will seek revenge for the death of his mother, whom she was responsible for killing, and instead schemes to regain influence by placing palace maids in the Crown Prince's quarters in hopes of producing a royal heir she can control.

Also known as: Lee Hee, King of Joseon

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.

Also known as: Han Seok-won

Do Seung Ji is the Chief Royal Secretary who, following the Gyesa Year Incident, serves as an advisor to Grand Queen Dowager Han. A cold, calculating strategist, he believes power rightfully belongs to the Han family and is determined to reclaim the kingdom from the Kim clan, aiming to rebuild the Han family's political dominance.

Also known as: Oh Shin-won, Left commander of Ikwisa

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.

Also known as: Yoon Se-dol

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.

Also known as: Heo Young-gam

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.

Also known as: Park Hong-nan

Park Hong Nan is regarded as the most beautiful woman in Boryeong even in her thirties, with vast knowledge and artistic talent honed during her years as the top courtesan in Hanseong. She serves as a guardian and aunt-like figure to Park Dal I, whose warnings and secrets set up early conflicts and mysteries. Five years ago she lost her beloved, Yeonwol, when his family was destroyed, and she has carried that sorrow ever since.

Also known as: Minister of Personnel Ja-gyeong

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.

Also known as: Cha Eun-woo

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.

Dal I's father became a eunuch due to poverty, alongside his younger sister becoming a courtesan to survive. Despite losing his manhood, he could not sever his feelings for the woman he loved, a court lady who would become Dal I's mother. He should have been executed for this forbidden relationship but survived thanks to the intervention of the late king and his sister's money, and now lives quietly as what locals call "Joseon's lucky guy."

Dal I's mother was once a court lady in the royal embroidery department who narrowly escaped execution after falling in love with a eunuch, Dal I's father. She now lives thanks to the sacrifice of her sister-in-law, who gave everything to save and employ the couple. She remains grateful and quietly apologetic toward that sister-in-law, living out a peaceful life with her husband.