Undercover High School

An elite NIS agent named Jung Hae-seong is demoted after a mission ends in failure. To win back his standing, he goes undercover at a high school to hunt down a missing cache tied to King Gojong. On campus he meets Oh Soo-ah, a perceptive teacher who reads him as the boy she once loved, stirring memories and complicating the mission. The undercover life collides with a personal history that keeps pulling him off script as he tries to balance danger with ordinary classroom moments. What unfolds stays taut and ambiguous, with twists kept just out of reach while the clock ticks.

Created by Im Young-bin and Choi Jeong-in, Undercover High School premiered in 2025. An original series blending action, comedy and drama, it features Seo Kang-joon and Jin Ki-joo leading a tight ensemble.

Reception likely hinges on its mix of genres and strong chemistry between a determined agent and a teacher who mistakes him for a lost love. The show explores identity under pressure, loyalty, and the conflict between duty and longing, all set inside a high school backdrop.