Teaser Trailer 3 added for the dramatic series MBC “Undercover High School” with Seo Kang-Joon, Jin Ki-Joo and Kim Shin-Rok. The dramatic series presents Seo Kang-Joon as AGENT NIS JUNG HAE-SEONG, which goes under cover at high school to locate the missing historic gold bars. Teaser three presents the next conflict between Jung Hae-Seong and Seo Myeong-Joo (Kim Shin-Rok). SEO MYEONG-JOO is the president of the Byeongmun Foundation and the Byeongmun high school, where Jung Hae-Seong ends up participating. His daughter Lee Ye-Na (Kim Min-Ju) is also a student in high school.

“Undercover High School” was broadcast on February 21, 2025 in South Korea.

Draw the synopsis by Asianwiki: Jung Hae-Seong (SEO Kang-Joon) is an AS agent for the National Intelligence Service (NIS). After a big incident occurred during an operation, Jung Hae-Seong receives a demotion. It is placed in an operation to locate the fate of the missing golden bars of King Gojong. For this mission, he hides his identity and goes under cover as a student at the prestigious Byeongmoon high school. There he meets Professor Oh Soo-A (Jin Ki-Joo) as a bedroom teacher.

Oh Soo-A is a contractual Korean history teacher with a right personality and has a strong affection for her students. One day, Jung Hae-Seong is transferred to the Byeongmoon high school and she becomes her bedroom teacher. She begins to see her first love, since her childhood days, overlaps in Jung Hae-Seong. His first love made him heart the greatest injury.