Undercover High School

Undercover High School

2025
8.2
1 Seasons
Action & Adventure Comedy Drama

Byungmoon, Korea’s top private high school, is rife with corruption, where status and success matter most. Hae-sung, a top NIS agent, goes undercover at Byungmoon to find Emperor Gojong’s hidden gold and uncover the truth behind his father’s disappearance. Cold and calculated, he sees the school as an obstacle—until he connects with students and a former crush and becomes a reluctant hero. Torn between duty and newfound bonds, can he still complete his mission?

Season

Episodes

Episode 1
Ep 1

The Emperor's Lost Gold

After a botched operation puts Hae-sung and his team in serious jeopardy, the only way for him to salvage his career at the NIS is to accept an assignment that seems almost hard to believe. Hae-sung and his team must infiltrate Byeongmun High School, one of Korea's most elite private institutions, to recover ten tons of gold bars worth a staggering 80 million dollars. With everything on the line, Hae-sung puts on a school uniform, and "Operation Undercover High School" begins.

Episode 2
Ep 2

Spooky Stories

Hae-sung comes dangerously close to blowing his cover while searching for the hidden gold in Byeongmun High School's eerie old building, barely escaping detection by Soo-ah, his sharp-eyed homeroom teacher. As he hears chilling rumors and faces tight security surrounding the building, he believes that's where he'll find the gold. While dealing with school bullies, Hae-sung begins plotting his next move to uncover the dark secrets lurking inside the old building.

Episode 3
Ep 3

Ghost Story Riddles

Hae-sung uncovers a crucial clue hidden within the old building, but Chairwoman Seo quickly learns its potential connection to the elusive gold bars. Sensing the connection, she keeps Hae-sung under close watch. Meanwhile, as Hae-sung delves deeper into the ghost stories surrounding the school, he finds himself caught in the escalating tension between Tae-soo and Dong-min, whose conflict ignites chaos throughout the school.

Episode 4
Ep 4

Joining the Student Council

Hae-sung attends the anti-bullying committee session with a key witness who clears his name, while Dong-min finally finds the courage to stand up for himself. With his name vindicated, Hae-sung uncovers the existence of another grandfather clock hidden in the student council room, and the only way to get closer to it is by joining the student council. With the help of his team, he tries to meet the strict requirements.

Episode 5
Ep 5

Student Council

Hae Seong and the team grow increasingly concerned that Su A's suspicions could threaten his undercover mission. However, Hae Seong defies the odds and successfully gains a spot in the student council. With this new role, his focus shifts to unraveling the mystery behind the old clocks. Meanwhile, a shadowy figure emerges, threatening to expose Hae Seong's true identity

Episode 6
Ep 6

Hye Seong's Father's Notebook

The school's security guard dies, leaving Hae Seong a notebook belonging to his missing father. The revelation is shocking, and he storms the NIS for answers. The answer pushes him away from the mission, and he takes time off. However, he resolves to continue but returns only to discover Su A witnessed it all

Episode 7
Ep 7

Episode 7

Ep 8

Episode 8

Ep 9

Episode 9

Ep 10

Episode 10

Ep 11

Episode 11

Ep 12

Episode 12

Cast

Seo Kang-joon

Seo Kang-joon

Jeong Hae-sung

Jin Ki-joo

Jin Ki-joo

Oh Su-ah

Kim Shin-rock

Kim Shin-rock

Seo Myung-ju

Kim Min-ju

Kim Min-ju

Lee Ye-na

Yoon Ga-i

Yoon Ga-i

Park Mi-jung

Kim Young-ah

Kim Young-ah

Im Chung-ha

Lee Hyeon-so

Lee Hyeon-so

Han Seung-jae