2025 • TMDB 8.0 • 12 episodes • Action & Adventure, Comedy, Drama
Overview
Undercover High School sends ace National Intelligence Service agent Jeong Hae-sung back to school — literally. Demoted after a mission goes wrong, he is given one last chance to redeem himself: enroll as a student at a prestigious high school and quietly track down King Gojong’s missing gold, rumored to be hidden somewhere on campus. The mission gets complicated fast when he crosses paths with his homeroom teacher, Oh Su-ah, who is convinced he is her long-lost first love, and with a school full of students, bullies, and secrets that refuse to stay buried. Blending high-stakes spy action with classroom comedy and a slow-burn romance, the series keeps its hero juggling homework, hallway politics, and dangerous enemies at the same time. Seo Kang-joon is effortlessly charming as the agent out of his depth, and Jin Ki-joo matches him as the teacher who sees far more than he expects. Funny, fast-moving, and genuinely sweet, Undercover High School is an easy binge that never takes itself too seriously.
Creator and Main Cast
Undercover High School was created by Im Young-bin and Choi Jeong-in for MBC. Seo Kang-joon stars as Jeong Hae-sung, the NIS agent posing as a high school student, opposite Jin Ki-joo as his teacher Oh Su-ah. The main cast also includes Kim Shin-rock as Seo Myung-ju, Kim Min-ju as Lee Ye-na, Yoon Ga-i as Park Mi-jung, and Kim Young-ah as Im Chung-ha. Each of the six leads appears across all 12 episodes.
Seasons Snapshot
Undercover High School is a miniseries of 12 episodes. It premiered on February 21, 2025, and concluded with the finale “Where The Stars Lead” on March 29, 2025. The story is told as one complete arc, from Hae-sung’s undercover enrollment to the final hunt for the missing gold.
Why Watch Undercover High School?
Undercover High School works because it commits fully to its ridiculous premise and then plays it straight. The spy plot delivers real chases, hidden treasure, and shadowy villains, while the school setting adds comedy gold: a trained agent struggling with exams, school lunches, and teenage drama. At its heart, though, is the warm chemistry between Seo Kang-joon and Jin Ki-joo, whose mistaken-identity romance gives the action real emotional stakes. If you like action-comedies with heart, this is one of the most purely entertaining Korean dramas of 2025.
Trailer
Watch the official trailer on YouTube: [Trailer] Viu Original, Undercover High School | Coming to Viu 21 Feb!
Where to Watch
In the US, Undercover High School streams on Rakuten Viki, OnDemandKorea, and Kocowa Amazon Channel. Availability was checked against JustWatch US listings on October 30, 2026, and may change over time.
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