This show doesn't deserve the 8,7 mark. I'm not the one who can watch a film while blocking my logical sense. The synopsis written here is much better than the storytelling in the show. They need much more details to show us the importance to draft the schoolers as reserve soldiers. Otherwise, it doesn't make any sense. Start from ep2, things got worse, the plot was pure garbage. A student died, but the military & the teacher tried to keep it secret? They didn't even inform his parents? Wth was that? Where was the responsibility? LoL. And suddenly, when they went outside, the streets were empty with no one. I was confused to see how they remained calm, asking "why it's so empty?" Did they evacuate the city? No detail at all, we were left guessing ourselves. In ep3, all the students opted to go home, but they were forbid. No details of how critical outside was. They were warned to be shot if they run. This is insane, it's not a duty but forcing to fight against their will. What government do that to their citizens, especially young & untrained ones? All adults go to the shelters, students fight the aliens. Oh, how sweet. ?
Watch it if you like all the screaming & running, maybe seeing pretty girls shooting guns. But if you care about logical story, avoid it. This is one of the worst kdrama in terms of the story.