Undercover High School is a South Korean drama released in 2025. It is a standard series with 12 episodes. The drama aired from February 21 to March 29, 2025, and was broadcast every Friday and Saturday. Each episode runs for around 1 hour and 10 minutes. The series belongs to the action, comedy, romance, and crime genres and carries a 15+ rating, suitable for teens and older viewers.
Table of Contents
📌 Synopsis
Jung Hae Seong is an elite agent working for the National Intelligence Service (NIS). Facing possible demotion, he is given one last mission. He must go undercover as a student at Byeongmun High School to find the whereabouts of King Gojong’s missing gold bars.
Disguised as a transfer student, Hae Seong enters the school and quickly realizes that the mission is more dangerous than expected. Inside the school, he meets O Su A, a passionate contract teacher of Korean history. Su A dreams of becoming a permanent teacher and believes strongly in honesty and education.
As Hae Seong adjusts to school life, his relationship with Su A slowly deepens. At the same time, he uncovers signs of corruption hidden within the school system. What starts as a simple undercover task soon turns into a battle against powerful figures operating behind the scenes.
With help from unexpected allies, Hae Seong risks his identity and career to expose the truth. The story blends secret missions, school politics, romance, and humor, keeping the tension high throughout.
🎭 Main Cast
- Seo Kang Jun as Jung Hae Seong / Jung Si Hyeon
- Jin Ki Joo as O Su A / O Bong Ja
- Kim Shin Rok as Seo Myeong Ju
🟦 Supporting Cast
- Jeon Bae Soo as An Seok Ho (NIS team 4 leader)
- Jo Bok Rae as Ko Yeong Hun (NIS agent)
- Yoon Ga Yi as Park Mi Jeong (NIS agent)
- Lee Seo Hwan as Kim Hyeong Bae (NIS director)
- Kim Min Ju as Lee Ye Na (Student council president)
- Park Jin U as Park Jae Mun (Byeongmun High School president)
- Oh Yong as Baek Gwang Do (Superintendent)
- Lee Min Ji as Kim Ri An (P.E. teacher)
- Noh Jong Hyun as Lee Jun Ho (Math teacher)
- Kim Young Ah as Im Cheong Ha (Su A’s mother)
🟨 Guest Cast
The drama features many guest appearances, including politicians, parents, gang members, journalists, and former school officials. These roles appear across different episodes and add depth to both the school setting and the crime investigation.
💭 Final Thoughts
Undercover High School combines undercover action with school life in a fresh way. The drama balances suspense, humor, and emotional moments while exploring corruption, trust, and identity. With strong performances and a fast-moving plot, it delivers an engaging story that mixes crime drama with youthful energy.
