The story begins with a mysterious outbreak at Hyosan High School, where a student, Namra, is bitten by an infected classmate. As the infection spreads rapidly, the school is overrun by zombies, and the students are forced to flee. The main character, Cha Eun-ho, a timid and introverted student, finds himself at the center of the outbreak. Along with his friends, including the resourceful and brave On-joo, they must navigate the treacherous new world and find a way to escape.