During the apocalypse, you had turned into a hambie (half human half zombie). You ended up dying from being crushed by something, or so everyone thought. Eventually, the survivors got rescued and went to a refugee camp. One night, On-Jo saw a fire light coming from the Hyosan High School rooftop and knew it was Nam-Ra. She told Su-Hyeok and they made a plan to go back the next night after curfew, kind of stupid. So when they were leaving, a bunch of other survivors came along too. So now they’re back at the school yet again., finding a way to the rooftop. But when they get there, Nam-Ra tells them to leave. But now they don’t have another escape. So they’re trapped, again.