The story, without the spoilers.
Jung Hae-seong is an elite agent of the National Intelligence Service, a man who has handled missions most people never hear about. His next assignment is the strangest yet: go undercover as a high-school student at Byeongmun High School and find a fortune in gold that vanished during the Japanese colonial era. The gold is hidden somewhere in the school, and Hae-seong must survive classes, exams, school bullies and a suspicious history teacher while he searches. Oh Soo-ah, his teacher, is warm, principled and completely unaware that her new student is a grown spy. As Hae-seong digs into the school's history, he discovers that the gold is connected to people who will kill to keep it hidden. Undercover High School aired on MBC from February 21, 2025, in twelve episodes, starring Seo Kang-joon and Jin Ki-joo. It is action, comedy and school drama in one very fun package. The school comedy, the action and the treasure hunt balance each other well.
A little curiosity. A new favourite.
Start with the story, meet the cast, and make room for one more episode.