Jeong Hae Seong, a transfer student who seems like he stepped out of a movie, quickly captures everyone's attention with his looks, charm, and smile. But beneath his perfect facade, he's not your average high schooler. Hae Seong is actually an elite NIS agent on a secret mission to uncover the hidden gold of the Joseon emperor. As he navigates high school life, he unknowingly opens up to his classmates, becoming increasingly entangled in unexpected connections. In the process, he uncovers the dark truth behind Byungmun High, a school deeply corrupted by its obsession with wealth and power. What starts as a treasure hunt soon turns into something much deeper, as Hae Seong seeks not just the gold, but also meaningful relationships. Teaming up with others, he fights back against the corruption in society. His undercover operation, filled with excitement, satisfaction, and a touch of bittersweetness, is about to begin!