The whole drama is one big problem. This drama is so bad that I decided to write a review for the first time to warn others. Don't waste your time. There are much better dramas worth watching.

Why do I think drama is so hopeless?

It's mostly about the plot. Or rather, the lack of it. What's the point of this story anyway? There isn't any. Really. Normally, every story has a beginning, a middle part and an ending. It reaches some conclusion.The story started out interesting . DAS wasn't as good as other zombie/monster dramas, but it was still interesting. Aliens invasion was quite original idea. And that's it. The further you go, the more nonsense the story becomes.

Part 2 begins by showing the students eliminating the aliens. It's promising. We know it's been a while since the incident when Sergeant Lee was killed. It seems that the children have matured and learned to take care of their own safety. You could not be more wrong. From this moment the story starts to get idiotic and full of plot holes.

First of all, why are the children alone? What happened to Kim Won Bin? Did he leave the children alone? Did he evacuate without them? Why do children talk about everyone who died and not him? He seems to have survived, so why did the writers suddenly forget about him?

As I wrote above, at the beginning of part 2 we see that the children have grown up. And suddenly... They start acting irrationally and getting hysterical again. All character development suddenly disappears. The other scenes don't make sense either. Why was the prison scene included in the series? The kids needed parts for a radio, so shouldn't they look for an electronics store in a deserted city? And how is it possible that the prisoners survived? We know that it's been at least a month since Sergeant Lee's accident by the time part 2 starts, and the town has already been abandoned. Did these prisoners live for more than a month without food, water and other necessities? And they were in such great condition? Seriously? Where is the logic?!

Another thing are the spheres. Where did the spheres come from? What did they want? What was their purpose? In the first part, it seemed that people were learning more and more about aliens, e.g. that they were sensitive to cold and noise, and that they could communicate. And in the second part? Aliens are mindless. They run to the prison because the children screamed a few times, but they didn't show up at the amusement park, where children make noise, So I am asking again where is the logic? At the end, we also learn that a weapon was invented, thanks to which the aliens were eliminated, but the spheres were still in the air. Why?

As for the ending, In my opinion it was stupid. But the stupidest thing was that nothing foreshadowed it. The writers didn't show us that Guk Yeong Soo is slowly going crazy, he just suddenly went crazy because his exam was canceled. Seriously?! PTSD would be much more convincing.

All in all, I do not recommend wasting your time watching this drama. The writers made this story as if they didn't respect the viewers. The series was very hyped, so they wrote anything, after all, the viewers would not notice.