100 Days of Deception

1. Synopsis

Gyeongseong's most skilled pickpocket and con artist Lee Ga-kyung, dreaming of earning enough to escape Joseon and start a new life abroad, agrees to go undercover as an interpreter at the Japanese Government-General of Korea for 100 days on behalf of the independence movement. There, she crosses paths with Kim Tae-woong, also known as Sato Hideo, an elite interpreter and the adopted son of Director-General Sato Shinichi. As the two become entangled in secrets and hidden loyalties within the colonial government, their lives intersect amid espionage, danger, and the growing struggle for Korean independence.

2. Cast

2.1. Main

• Kim You-jung as Lee Ga-kyung / Geum Seo-hee^[1]

Gyeongseong's best pickpocket who dreams of going to America. While saving money to achieve her goal, she accepts an offer from the anti-Japanese independence group Gu-guk-dan and becomes a spy, infiltrating the Government-General of Korea disguised as an interpreter for 100 days.

• Park Jin-young as Kim Tae-woong / Sato Hideo^[2]

The adopted son of Sato Shinichi and a newly appointed elite interpreter at the Government-General of Korea. Fluent in English, Japanese, and Korean, he returns to Korea after more than 10 years abroad and takes on an important role as an interpreter.

• Kim Hyun-joo as Yoo So-ran^[3]

A sniper for the anti-Japanese independence group Gu-guk-dan who takes up arms in pursuit of revenge. After becoming entangled with Sato Shinichi through events in the past, she returns to Korea after more than 10 years under a new identity as a Chinese woman and enters into a marriage of convenience with Yoo Phillip. While carrying out an assassination operation against Sato, she proposes a life-threatening deal to Lee Ga-kyung.

• Lee Moo-saeng as Yoo Phillip^[4]

A Korean-American and correspondent for an American media company stationed in Gyeongseong. As a member of Gu-guk-dan and a journalist, he uses his position and knowledge of international affairs to put pressure on the Political Chief of the Government-General, while maintaining a marriage of convenience with Yoo So-ran.

• Jin Seon-kyu as Sato Shinichi^[5]

The newly appointed Director-General of Political Affairs and adoptive father of Sato Hideo. An ambitious man willing to do anything for success and advancement, he becomes the primary target of Gu-guk-dan.

2.2. Supporting

2.2.1. Sato household

• Seo Jeong-yeon as Ryu Gwan-sil / Yanagi^[6]

A Korean housekeeper who has worked for the Sato family for many years. She helps Tae-woong retain his Korean language and is one of the few people who remembers his mother.

• Oiko Kiko as Sato Hanako

Sato Shinichi's daughter and Tae-woong's younger half-sister. She has used a wheelchair since birth and is particularly close to Tae-woong. After returning to Gyeongseong, she becomes curious about her Korean mother, who died giving birth to her.

2.2.2. National Salvation Corps

• Park Jung-yeon as Kim Myeong-nam^[7]

The only daughter of Kim Seung-eok, the president of Joil Textile and a prominent pro-Japanese collaborator. She secretly loves Lee Yeong-bok and becomes involved with the National Salvation Corps after following him. She secretly sells jewelry given to her by her father to help fund the organization.

• Lee Seon as Lee Yeong-bok

The secretary of Kim Seung-eok at Joil Textile and a member of the National Salvation Corps. Born into a family that had served the Kim family for generations, he became Seung-eok's secretary because of his intelligence. He secretly diverts company funds to support the independence movement and harbors feelings for Myeong-nam.

• Kim In-kwon as Han Cheol-ryong^[8]

One of the senior members of the National Salvation Corps. After being arrested and imprisoned during an earlier operation, he went to the organization's headquarters in Shanghai and has recently returned to Gyeongseong. He remains unmarried, claiming that he will not marry until Korea gains independence.

• Choi Deok-moon as Gwak Un-hak^[8]

A longtime member of the National Salvation Corps and an associate of Han Cheol-ryong. He works as a traditional Korean medicine doctor at Hanseong Korean Medicine Clinic in Jongno, where most of his patients are poor Koreans who cannot afford treatment.

• Lee Do-gun as Jang Jeong-yeop

A member of the National Salvation Corps who works as Gwak Un-hak's assistant at Hanseong Korean Medicine Clinic. Married with three children and expecting a fourth, he keeps his involvement in the independence movement secret from his family because he does not want to worry them.

• Jeon Seok-chan as Kim Chi-geon

A doctor at the hospital affiliated with Keijo Imperial University. After witnessing students from Severance Medical College suffer for participating in the March 1 Movement, he becomes involved in the independence movement.

• Go Se-bin as Hwang Gyu-yeong

A nurse at the hospital affiliated with Keijo Imperial University. Inspired by nurse Park Ja-hye, who joined the independence movement after witnessing the March 1 Movement, she hopes to work in a hospital serving Koreans after independence.

2.2.3. Government-General

• Kim Joong-hee as Fukuda^[6]

The Director of the Police Bureau of the Government-General of Korea. He previously served as a high-ranking police officer at the Jongno Police Station alongside Sato Shinichi, whom he met during his military service. After Sato returns to Gyeongseong, Fukuda pledges his loyalty to him.

• Kim Do-hyun as Suzuki^[6]

An English interpreter for the Government-General of Korea and Tae-woong's superior. Trusted by Sato, he manages foreign affairs at a time when diplomacy is important. He speaks English, Japanese, and Korean.

• Kouri Yuka as Yamada^[6]

Sato Shinichi's secretary. Originally from Tokyo, she obtains her position through her uncle, a senior official in the Government-General's Interior Affairs department. She is somewhat naive and clumsy, has a strong interest in fashion, and becomes shy around Tae-woong after falling for him at first sight.

2.2.4. Gyodang-ri

• Hong Sa-bin as Inoma^[6]

A rickshaw driver who lives with Ga-kyung in the shantytown and works with her as a pickpocket. He became an orphan after his parents died during the March 1 Movement. He is strong and fast but is illiterate and has no shame about it.

• Kim Ra-hee as Bang Kkot-nim

A resident of the Gyodang-ri shantytown who lives with Ga-kyung and Inoma. She lost her parents during an epidemic and became unable to walk. After Inoma took her in, she came to regard him as an older brother.

• Lee Seok as Ma Mun-mak

A thug who lives in the shantytown and controls its child pickpockets. He is frequently drunk and mistreats those who fail to meet their daily quotas. He resents Ga-kyung's contempt for him and looks for an opportunity to retaliate.

• Unknown as Lee Bak-chun

A former farmer who was driven from his hometown after organizing a dispute against the exploitation of farmers by Japanese landowners. After wandering between places, he settled in Gyodang-ri, where he has lived for about ten years. He has a disability in one leg.

• Lee No-ah as Im Geum-ok

A resident of Gyodang-ri who lost her parents in the 1925 Great Flood of the Han River and became homeless with her younger sibling. Her sibling later left for a farm in Manchuria, and she waits for letters while making a living by weaving and selling straw mats.

• Yang Jo-ah as Kim Jo-i

A mysterious woman whose origins are unknown. When she first appeared in Gyodang-ri, she was carrying a deceased infant, which the villagers buried. Since then, she has carried a handmade doll wrapped in cloth as though it were a baby.

2.2.5. Family

• Lee Ki-young as Kim Seung-eok^[6]

The president of Joil Textile, one of the largest textile companies in Korea, and a prominent pro-Japanese collaborator. He is the father of Kim Myeong-nam and is proud of her despite losing her mother at a young age. He regrets not having a son and plans to find a suitable son-in-law to inherit his company.

2.2.6. Others

• Go Han-min as Mitarai^[6]
• Jeon Yung-beop as Song Jeon
• Kim Dong-young as Park Se-hwan
• Kang Ha-eun
• Choi Ji-woo

3. Production

3.1. Development

The series is developed by Studio Dragon and produced by Studio Dragon and Nangman Crew. Yoo In-shik directs the series from a screenplay written by Ryu Bo-ri, marking their first collaboration. Yoo previously directed Dr. Romantic (2016–2023) and Extraordinary Attorney Woo (2022), while Ryu wrote Do You Like Brahms? (2020) and Trolley (2022).^[9][1]

The first script reading took place on February 6, 2026.^[4]

3.2. Casting

In October 2024, Kim You-jung was reported to have been cast in the lead role.^[1] The following month, Kim Hyun-joo was reported have received an offer to join the series.^[3] In July 2025, Park Jin-young was reported to have been cast as the male lead,^[2] followed by Jin Seon-kyu in December.^[5] tvN officially confirmed the main cast, including Lee Moo-saeng, in February 2026.^[4]

3.3. Filming

Principal photography began in March 2026.^[4] Filming locations include Nonsan Sunshine Land in South Chungcheong Province, which was confirmed as a key filming location and main backdrop for the series and was previously used in the television series Mr. Sunshine.^[10]

4. Release

100 Days of Deception is scheduled to premiere on tvN on October 10, 2026, and will air every Saturday and Sunday at 21:10 (KST). It will also be available for streaming on TVING in South Korea and Netflix globally.^[10][11]

5. Marketing

On July 2, with 100 days left until the drama's premiere, a special teaser was released, continuously highlighting the keyword "100" to captivate viewers.^[12]

On August 11, 2026, tvN announced a special exhibition titled 100 Days of Deception Special Exhibition: 1932 Gyeongseong, Becoming a Spy at the Seoul Museum of History. The exhibition presents the setting and characters of the series. The first-floor lobby exhibition runs from August 14 to September 27, 2026, while a display in the museum's third-floor permanent exhibition area runs from August 14 to November 29.^[13]

On September 21, tvN launched an interactive promotional website for 100 Days of Deception, allowing users to explore content related to the series and its 1932 Gyeongseong setting.^[14]

On September 22, tvN announced a special broadcast titled 100 Days of Deception: Secret Documents, scheduled to air on October 3, 2026, at 22:30 (KST), one week before the series premiere. The broadcast features the main cast introducing the series and their characters, with television personalities Tak Jae-hoon and Kim Jong-min serving as hosts.^[15]