KRPrime Video +3

Jung Hae Seong is a top agent from the National Intelligence Service who is on the verge of being demoted. To prove himself, he takes on a dangerous undercover mission at Byeongmun High School, where he must track down gold bars once owned by King Gojong. Disguised as a student, he blends into school life while quietly investigating the case.

At the school, he meets O Su A, a contract Korean history teacher who hopes to secure a permanent teaching position. As they spend more time together, the two begin to grow closer. During his investigation, Hae Seong uncovers signs of deep rooted corruption within the school. With the help of those around him, he sets out to challenge the powerful figures behind it and bring the truth to light.