The virus makes infected people extremely aggressive, but some individuals show traits — they are infected yet retain some consciousness and immunity to full zombification. The series explores friendship, sacrifice, bullying, and social collapse among teenagers.

A zombie virus suddenly breaks out at Hyosan High School. Students and teachers become trapped inside the school as the infection spreads rapidly through bites. A small group of students must fight to survive, escape the building, and reach safety while the entire city outside collapses into chaos.