Our Unwritten Seoul

Synopsis

Yoo Mi-ji and Yoo Mi-rae are identical twins with opposite personalities and lifestyles. Mi-ji was a promising sprinter, but she has now quit sports due to an injury and is living a free-spirited life in her hometown of Duson-ri, taking care of her grandmother without a plan for her future. Mi-rae has always been a model student and is a perfectionist working at a public corporation in Seoul. When Mi-ji finds out that her sister is struggling with workplace bullying, she suggests that they swap places for a few months.

Cast

Main

Park Bo-young as Yoo Mi-ji and Yoo Mi-rae

Lee Jae-in as teen Yoo Mi-ji and Yoo Mi-rae

Yoo Mi-ji: The younger of the twins, she works various jobs in Duson-ri, having chosen to stay in her hometown to care for her grandmother after the latter's stroke. She was a promising athlete but lost her chance to compete in the Olympic Games due to a sports leg injury.

Yoo Mi-rae: The older twin; she works at a corporate job in Seoul. She is academically gifted but lacks physical strength due to an underlying medical condition.

Park Jin-young as Lee Ho-soo, a high school classmate of the Yoo twins who is now a lawyer at a prestigious law firm. He lost his hearing in his left ear following a car accident in which his father died. He has liked Mi-ji since they were young.

Park Yoon-ho as teen Lee Ho-soo

Kang Ye-chan as child Lee Ho-soo

Ryu Kyung-soo as Han Se-jin, a man who starts as a hedge fund chief investment officer but later becomes a strawberry farm owner in Duson-ri.

Supporting

Jang Young-nam as Kim Ok-hee, the twins' mother and an elementary school lunch lady. She is a strong-willed single mother who has been the head of her household for nearly 30 years. She favors Mi-rae.

Cha Mi-kyung as Kang Wol-soon, the grandmother of the twins and a former beauty salon owner. She helped with childcare and housework before suffering a stroke.

Moon Dong-hyeok as Song Gyeong-gu, the assistant manager of Kyunggu Mart, as well as Mi-ji's ex-boyfriend and current best friend.

Yoo Yoo-jin as Park Ji-yoon, a high school friend of Mi-ji and Mi-rae.

Im Chul-soo as Lee Chung-goo, Lee Ho-soo's senior colleague and a highly capable lawyer known for his impressive win rate.

Kim Sun-young as Yeom Beon-hong, Lee Ho-soo's mother and vice principal of an elementary school. She has been a long-time neighbor of the twins' family in Duson-ri.

Shin Jeong-won as Hwang Ji-soo, Lee Ho-soo's secretary at Wongeun Law Firm.

Jeong Seung-gil as Choi Tae-gwan, director of the Planning and Coordination Bureau.

Lee Si-hoon as Shin Gyeong-min, head of the Planning Strategy Team.

Go Ae-ri as Ahn Mi-jung, a member of the Planning Strategy Team.

Yang Dae-hyeok as Hwang Yun-ho, a member of the Planning Strategy Team.

Sim So-young as Lee Hyo-kyung, a member of the Planning Strategy Team.

Special appearance

Kim Joo-hun as Ho-soo's father

Production

Development

Our Unwritten Seoul was initially a KBS drama, but they encountered difficulties in casting due to the declining competitiveness of their channels. KBS then approached Studio Dragon to co-produce the series and signed a MOU with CJ ENM, handing the drama over to tvN.

Park Shin-woo, who directed Lovestruck in the City (2020–2021), was attached to direct, and Lee Kang of Youth of May (2021) was reported to write the screenplay in December 2024. The series was planned by Studio Dragon and co-produced by Monster Union, Higround, and Next Scene. Screenwriter Kang shared that she wrote the series to tell "stories of people who look fine on the outside but are already wavering and exhausted inside." She imagined how nice it would be if a person who looked exactly like her could replace her, but at the same time wondered if her twin's life would be more peaceful than hers, thus deciding to write about two twin sisters swapping lives.

Casting

On July 25, 2024, Newsen reported that Park Bo-young had received an offer for the series, with Ten Asia confirming her appearance on the same day. On September 26, BH Entertainment told Newsen that Park Jin-young was considering the drama as the next project following his discharge from the army. On October 8, News 1 reported that Ryu Kyung-soo had joined the series as one of the leads. On December 3, Park Bo-young and Jin-young were confirmed to appear.

Park Bo-young received the script one year before the series went into production and decided to participate after reading the first episode and being favorably impressed by it. Although there was neither a director nor a broadcaster yet, she thought she would never have a similar opportunity again; she also wanted to play a strong character that would contrast with the sweet and cheerful ones she had played up to that point. Although Park had already played two different roles in Oh My Ghost (2015), she found Our Unwritten Seoul more difficult because she could not imitate another actress' performance to differentiate the two characters: she therefore started from the small details that made Mi-ji and Mi-rae unique, distinguishing them in their voice, clothing, makeup and hairstyle.

Park Jin-young was drawn to the narrative centered on victims or the weak, and found it fascinating that Lee Ho-soo, who is deaf in one ear, tried to listen to others better than a healthy person could. Hong Sung-won had initially auditioned for the roles of Ho-soo and Gyeong-gu before the director offered him the part of Kim Tae-yi.

Filming

Principal photography began at the end of 2024. The series joined the promotional campaign "Seoul, My Soul" and throughout the episodes, many attractions of the metropolis appear, such as the park north of Dongjak Bridge, the rainbow fountains of Banpo Bridge, Seongsu Naknak, Dongdaemun Design Plaza, Gwangtonggyo Bridge in Cheonggyecheon, Hanbit Square, the LG Twin Towers in Yeouido, Myeong-dong and the hanok district. The countryside scenes were filmed in Mungyeong, Gyeongbuk and Damyang, South Jeolla Province; filming also took place in Dangjin, Gwangju, Suncheon and Hapcheon.

Original soundtrack

The soundtrack features artists such as Choi Yu-ree, 10cm, Hong Isaac, dori, and Elaine. It was led by music director Nam Hye-seung.

Album

Tracklist

Reception

Critical response

On the review aggregator website Rotten Tomatoes, 100% of 5 critics' reviews are positive.

Our Unwritten Seoul was well received by both critics and audiences. It was praised for its direction, solid screenplay containing words of comfort for modern people, and the actors' performances, in particular Park Bo-young's, who was appreciated for having distinguished the two sisters naturally, without unnecessary emotional excesses.

The popularity of Our Unwritten Seoul was attributed to its greatly empathetic approach to youth, depicting the confusion of a generation that despises itself, but gradually grows and overcomes its self-hatred when it realizes that everyone is suffering from something, creating a ripple effect similar to that of a self-help book, and giving courage to those who were facing difficult challenges. Pop culture critic Jung Deok-hyun observed that, through the fantasy of exchanging lives with another person, the series illustrated the process of finding the true self, forgotten by living without much thought, as well as highlighting an absurd reality in which people survive by thinking they are wrong compared to others. Fellow critic and activist Baek Su-jeong appreciated that disabled people were not portrayed stereotypically as incompetent, marginalized, or geniuses suffering from "savant syndrome," but as people who live their lives and work, taking the successful lawyer Lee Chung-goo as an example.

Viewership

Our Unwritten Seoul premiered on South Korean cable television channel tvN on May 24, 2025. Its first episode recorded a viewership rating of 3.6%, reaching 5% with the second episode. The ratings grew over the weeks, reaching a national average of 8.4% by the final episode, the highest among the programs in its time slot. It became tvN's highest-rated Saturday and Sunday drama to date, surpassing Resident Playbook. The series was distributed in Korea and internationally on TVING and Netflix; on the latter, it ranked third among the most-watched non-English language programs for the week of May 26 – June 1, 2025. It stayed in the top 10 for five consecutive weeks, garnering more than 112 million hours of viewing.