4 Best Moments Of Seo Kang Jun And Jin Ki Joo From “Undercover High School”

Mar 05, 2025

Seo Kang Jun and Jin Ki Joo are captivating viewers with their standout performances in “Undercover High School”!

“Undercover High School” is a comedy action drama about a National Intelligence Service (NIS) agent who goes undercover as a high school student to track down Emperor Gojong’s missing gold. Seo Kang Jun stars as Jeong Hae Seong, an ace NIS field agent who disguises himself as a student at Byungmun High School as part of a secret mission. Jin Ki Joo stars as Oh Soo Ah, a temporary Korean history teacher and Jeong Hae Seong’s homeroom teacher.

Here are four of the most memorable moments highlighting Seo Kang Jun’s and Jin Ki Joo’s standout performances and dynamic interactions:

Spoilers

Jeong Hae Seong’s struggle to fit in at high school

As part of his undercover mission, Jeong Hae Seong must pose as a high school student—but blending in with teenagers proves to be harder than expected. When his classmate Choi Soo Jin (Shin Ga Eun) asks, “What’s your social media ID? I’ll send you an anonymous message,” he misinterprets her words and abbreviation for “anonymous message” and awkwardly pretends to know what type of “anonymous message” she is talking about.

While exploring the school’s old building, Hae Seong encounters a group of troublemakers. When they try to boss him around, he snaps back, “Take it easy,” refusing to back down. But just as tensions rise, a vision of Ahn Seok Ho (Jeon Bae Soo) appears with a glowing aura, reminding him to stay in control. Reluctantly, Hae Seong gives in to avoid escalating the situation.

How substitute teacher Soo Ah navigates school life

One day, Soo Ah witnesses Park Tae Soo (Jang Sung Bum) bullying Lee Dong Min (Shin Jun Hang). After much thought, she anonymously posts on the school bulletin board, exposing Tae Soo for illegal gambling and harassing Dong Min.

When Vice Principal Baek Kwang Doo (Oh Yong) demands to know who wrote the post and singles her out, Soo Ah dramatically slams her desk and exclaims, “Who could it possibly be?” Instead of backing down, she becomes even more animated, pointing fingers at others and shouting, “I will root out the traitor and personally deliver their head!”—a moment that has viewers laughing.

Jeong Hae Seong and Oh Soo Ah’s hilarious chemistry

Every time Hae Seong and Soo Ah cross paths, their nonstop bickering keeps viewers entertained. Soo Ah is instantly drawn to Hae Seong when she first sees him drinking at her mother’s store. However, her admiration quickly turns to suspicion when she later discovers he is the new transfer student in her class—immediately labeling him a troublemaker.

During class, Soo Ah tries to wake Hae Seong from a nap with a light tap. Startled, he instinctively chops her neck, shocking the entire class. Their chaotic interactions don’t stop there—when Soo Ah stumbles toward him mid-conversation, Hae Seong reflexively steps aside, sending her tumbling to the floor.

The double kiss that had everyone talking

A surprising double kiss involving Hae Seong, Soo Ah, and NIS Domestic Team 4 had viewers buzzing.

Concerned about Hae Seong’s health, Soo Ah visits his rooftop room. However, she accidentally steps on a massage ball, loses her balance, and crashes into Hae Seong—causing the two to fall and accidentally lock lips. Meanwhile, inside a closet, NIS Team 4 agent Park Mi Jung (Yoon Ga Yi) is hiding as her teammate Go Young Hoon (Jo Bok Rae) struggles to hold back a sneeze. In an effort to prevent the sneeze, Park Mi Jung boldly locks lips with Go Young Hoon, only for the shock to cause them to tumble outside the closet and get caught by Oh Soo Ah.