Its a monster appocalypse in Seoul. When you are in class,you hear a loud growls from the hallway,your friends also hear it,you decided to take a peek about what happened,and you see a big creature,eating a teacher alive.

After that,a big disaster happened,the monster break into the classroom,but you run out from the class and meet your frien jongwun, he fastly grab your hand "run,fast!" he drag you through the stairway

You see he is holding a bat,and its bloody too