100 Days of Deception — A pickpocket goes undercover in a Gyeongseong spy romance

In Gyeongseong in 1932, pickpocket Lee Ga-gyeong (Kim You-jung) enters the Japanese Government-General of Korea as a spy for the resistance group Gugukdan. This tvN drama combines espionage and romance through an English interpreter trainee hiding her identity and a senior interpreter who suspects her. CJ ENM series introduction · TVING synopsis

Information checked: October 30, 2026

Introduces the opening undercover premise and character relationships. Includes colonial violence and the deaths of family members.

A hundred-day assignment in exchange for passage to America

Ga-gyeong wants to start a new life in America. Gugukdan sniper Yoo So-ran (Kim Hyun-joo) notices her quick thinking, skill at lying and command of English, and proposes an undercover assignment. In return for a hundred days as a spy, Ga-gyeong is promised a way to America. Character teaser coverage · Episode-three coverage

Korean-American correspondent Yoo Philip (Lee Moo-saeng) arranges the trainee position, and Ga-gyeong takes the name Geum Seo-hui. She must pass information from inside the Government-General to Gugukdan while maintaining her cover in front of her superiors and colleagues. TVING: episodes 3–4 · How she obtains the position

Sato Hideo already knows the woman behind the new name

Ga-gyeong’s senior interpreter, Sato Hideo (Park Jinyoung), is the adopted son of Sato Shinichi (Jin Sun-kyu), the Government-General’s Director-General of Political Affairs. His Korean name is Kim Tae-woong. He hopes for independence while wanting recognition from the adoptive father who raised him. He has met Ga-gyeong before her new appointment, so her arrival under another name makes him suspicious. Ilgan Sports: character background · TVING: episodes 3–4

Tae-woong grows drawn to Ga-gyeong despite his doubts about her. Director Yoo In-shik describes the romance as a situation in which trying to win over an adversary leads to falling in love. TVING: episode 4 · Director interview

So-ran, the woman recruiting Ga-gyeong, lost her daughter to Japanese police and has spent years separated from her husband. She poses as Philip’s wife to approach Sato for an assassination attempt. So-ran and Philip’s cover

Kim Hyun-joo · © tvN / CJ ENM · Official image source

Espionage through interpreting in a multilingual city

Yoo In-shik and Kim Yoon-jin direct, with a screenplay by Ryu Bo-ri. Yoo explains that he chose Gyeongseong Station for the opening because the railway represented both modernization and colonial control. He envisioned the principal characters appearing in a station filled with unfamiliar arrivals and different languages. Production interview

Ga-gyeong works as an English interpreter trainee in a city where Japanese, English and Chinese are spoken. Yoo identifies the combination of interpreting and espionage as a source of suspense, while describing romantic-comedy scenes alongside spy action. The director on genre and staging

Kim You-jung and Park Jinyoung · © tvN / CJ ENM · Official image source

Korean TVING availability and the official teaser

The series premiered on tvN on October 10, 2026, and is still airing. On October 30, its Korean TVING page listed episodes 1–6 and displayed a subscription prompt. Playback conditions may vary by account, subscription and location. Official series information · TVING series page

In TVING’s weekly VOD unique-viewer figures for October 19–25, it ranked first both overall and among dramas. TVING’s official weekly report

The official tvN character teaser introduces Ga-gyeong’s bargain, her cover identity and the principal relationships. Watch the official teaser

Official poster · © tvN / CJ ENM · Official image source

Early reviews: performances, tonal shifts and the opening setup

Performances draw praise in both Korean and international coverage. Ilgan Sports journalist Kim Ji-hye credits Kim You-jung with combining Ga-gyeong’s playfulness and the weight of the period, and praises Kim Hyun-joo’s portrayal of family loss and the altered speech she uses to maintain her cover. Flickonclick’s Mohan Nasre also welcomes the lead performances and the combination of espionage, romance and historical setting. Kim Ji-hye · October 12, 2026 · Episodes 1–2 · Mohan Nasre · October 11, updated October 12, 2026 · Episodes 1–2

Nasre’s reservation concerns the quick movement between comedy, romance, spy action and historical tragedy, which may leave emotional scenes too little room to breathe. He also notes that the many characters and secrets can make the opening difficult to follow. Flickonclick review

In a research-based assessment using coverage of the first four episodes, DaebakDaily’s Huzaifa values the heroine’s practical survival concerns and a relationship developing through suspicion, but finds that the crowded introductions delay the main undercover assignment. Huzaifa · October 22, 2026 · Research-based assessment of the opening four episodes

The linked reviews discuss scenes and events in greater detail than this introduction.

If you’re looking for similar stories

Mr. Sunshine · Netflix — A man who left for America as a boy returns to Joseon and meets a noblewoman. It is a companion for viewers interested in romance intertwined with choices made during historical upheaval.

Sources and image credits

Images: tvN / CJ ENM. Each caption links to the official series page.

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