NIS agent Jung Hae-sung, portrayed by Seo Kang Joon, delves deeper into the enigma of Emperor Gojong's missing gold bars. Posing as a student, he infiltrates the student council to access vital information. The plot intensifies when Hae-sung receives a cryptic phone call, propelling him into a perilous meeting that could alter his investigation's course. As secrets unravel, Hae-sung grapples with trust and betrayal, navigating the treacherous waters of high school life while pursuing the truth.