

8.769 minSeason 1 • Episode 12
LatestDespite getting badly injured, Hae Seong manages to call Su A and his team. They conclude that the only evidence they can secure is the flash drive that contains the voice recording of Principal Park murdering Director Kim Hyung Bae. After finding out that an arrest warrant had been issued for her, Seo Myeong Ju decides to take a special measure to end everything.
Ace NIS agent Jung Hae-seong is demoted after a mission failure. He goes undercover at a high school to locate King Gojong's missing gold, meeting his teacher Oh Soo-ah, who sees him as her lost first love, stirring old heartbreak.
Acting
Seo Kang-joon's physical comedy is criminally underrated
Writing
Balances slapstick with genuinely moving backstories
Production
That classroom set feels lived-in, not generic
Trivia, insights & behind the scenes
King Gojong's missing gold references real disputed historical artifacts from Japanese colonial period, adding unexpected weight to the premise.
Seo Kang-joon trained for three months in actual NIS combat techniques, then mostly used them for pratfalls in a school uniform.