When hostile aliens launch a worldwide invasion, the South Korean military has no choice but to recruit all third-year high school students to join the forces. After arriving at Seongjin High School, platoon leader Lee Chun Ho (Shin Hyun Soo) guides students through rigorious training for combat. Meanwhile, class teacher, Park Eun Yeong (Im Se Mi) is determined to keep her students safe as they fight this war against aliens to save their world from the brink of extinction. Based on the webtoon written by Ha Il Kwon, this 2023 South Korean drama series was directed by Sung Yong Il.