Undercover High School (Korean: 언더커버 하이스쿨) is a 2025 South Korean action comedy spy television series written by Im Young-bin, directed by Choi Jung-in, and starring Seo Kang-joon, Jin Ki-joo, and Kim Shin-rok. The series depicts a man who is an NIS agent goes undercover as a high school student. It aired on MBC TV from February 21, to March 29, 2025, every Friday and Saturday at 21:50 (KST). It is also available for streaming on TVING and Wavve in South Korea, and on Viu, Kocowa and Viki in selected regions.
Contents
Synopsis
Jeong Hae-seong, a demoted NIS agent following a major incident that occurred during an operation, is tasked with a special mission of tracking down the whereabouts of Emperor Gojong's missing gold bars. Hae-seong hides his identity, goes undercover as a high school student at Byeongmun High School, and meets Oh Su-a, his homeroom teacher. Su-a, a devoted teacher to her students, begins to notice the similarities between Hae-seong and her childhood first love, who left her heartbroken and filled with painful memories.
Cast and characters
Main
Seo Kang-joon as Jeong Hae-seong / Jeong Si-hyun
Yu Ji-wan as young Jeong Si-hyun
An ace field agent of Domestic Team 4 of the NIS who is given a special mission to find Emperor Gojong's gold bars.
Jin Ki-joo as Oh Su-a / Oh Bong-ja
Park Seol-ha as young Oh Bong-ja
Hae-seong's homeroom teacher who is a temporary Korean history teacher at Byeongmun High School.
Kim Shin-rok as Seo Myeong-ju
Chairwoman of the Byeongmun Foundation and Byeongmun High School who is Ye-na's mother.
Supporting
Jeon Bae-soo as An Seok-ho
Head of the Domestic Team 4 of the NIS and is like a second family and father to Hae-seong.
Jo Bok-rae as Go Yeong-hun
Hae-seong's junior agent at the NIS.
Yoon Ga-i as Park Mi-jeong
Hae-seong's junior agent at the NIS.
Lee Seo-hwan as Kim Hyung-bae
Director of domestic division of the NIS.
Im Cheol-hyeong as Gong Jin-sang
Seok-ho's classmate and the head of the NIS Domestic Team 1.
Kim Min-ju as Lee Ye-na
Student council president of Byeongmun High School who is Myeong-ju's only daughter.
Park Se-hyun as An Yu-jeong
Student council member of Byeongmun High School who is Seok-ho's daughter and Hae-seong's younger sister.
Jang Seong-beom as Park Tae-soo
A student council member of Byeongmun High School who is a son of a three-term National Assembly member from Yeouido.
Lee Hyun-so as Han Seung-jae
Student council member of Byeongmun High School who is a son of the CEO of Han Young Law Firm, one of the top law firms in South Korea.
Production
Development
The series began its production and is planned by Namkoong Seong-woo, written by Im Young-bin, directed by Choi Jung-in, and produced by Neo Entertainment and Slingshot Studios. In addition, it aimed to air in early 2025.
Casting
In March 2024, Seo Kang-joon was reportedly in talks as the lead actor and his agency told the media that he was positively reviewing it. This was Seo's first work after completing his military service in May last year as well as comeback to the small screen after 2022 TV series Grid. In May 2024, Jin Ki-joo and Kim Min-ju were reportedly cast to work along Seo with the former as the female lead in the series. In June 2024, MBC confirmed that Seo and Jin would appear as the lead actors for the series. This was also Seo's first MBC drama comeback after appearing in Splendid Politics (2015). The same month, Kim Shin-rok was reportedly confirmed to cast July 2024.
Filming
Principal photography began in the first half of 2024.
Original soundtrack
Release
MBC announced that Undercover High School would be broadcast in a Friday–Saturday timeslot in February 2025. The series was confirmed to premiere on MBC TV on February 21, at 21:50 (KST). It is also available for streaming on TVING and Wavve in South Korea, and on Viu, Kocowa and Viki in selected regions.
