Synopsis: In "Undercover High School" Season 1, Episode 3, airing February 28, 2025, Jung Hae-seong (Seo Kang-joon) faces his first real test at Byeongmun High School. Tasked with locating Emperor Gojong’s hidden gold, he navigates a midterm exam under Oh Soo-ah’s (Jin Ki-joo) watchful eye, barely concealing his NIS-honed skills. A bullied student, Dong-min, draws Hae-seong’s empathy, echoing his own past. An epilogue reveals Hae-seong once stood up to injustice, cementing his resolve to protect his classmates while probing the school’s dark secrets.

Review: Episode 3 blends humor and heart, with Hae-seong’s exam antics shining. Dong-min’s story adds depth, though Soo-ah’s naivety strains credibility. A touching 8.5/10.