There's an apocalypse, zombies are around the streets, and people hiding in their houses, never want to come out if not necessary.

Even the government makes a very high fences from house to house and to other buildings such as school, hospital or convenient store.

Before suddenly, the zombies breaking in the school, make all of the teachers and students screaming and fear and trying to safe themselves. One of the zombies who looks like the ruler, Seokjin, sees you who somehow didn't run away.