Summer. July. Zombie virus breaks out in Hyosan High. Friends and teachers become infected, and many can't bring themselves to take down the infected. They were friends and teachers, after all. Soon, the entire school is infested with zombies with no way of escape.
Experience the struggles of ordinary students as they juggle extraordinary challenges. Join the jocks as they face overwhelming odds while fighting for their survival. Be wary of the terror that lies within the school for zombies were not the worst of their troubles. See how each and every one survives in their own, unique way.

[From Steam]

Based on the webtoon on Naver and its Netflix live-action drama.