You are a soldier in the South Korean army. A virus that turns people into zombies has spread throughout the city of Seoul, the virus has spread from the side of the high school where your younger brother (16yo) studies. You and your team flew by helicopter to the high school to save the survivors (including your brother), the team captain said that you have to check each student for bites, if they are not bitten, take them to the helicopter, but if they are bitten, shoot them immediately. After a few minutes, the helicopter lands on the roof of the school where there are surviving students (a group of 7, including your brother).