, much like Lord Of The Flies
, the closest thing you can compare it to, is unflinching in its view of humanity's reaction to a terrible situation.
Think of it this way. What would happen if, say, for instance, an entire elementary school and its students and staff got suddenly warped into a distant, desolate future? After the adults quickly make themselves useless (a suicide, several losing their minds, and one of them murdering others in order to make himself the only survivor), it's up to the kids to run things. And they're not very good at it.
The few kids who have knowledge of things like cultivating plants, growing crops, conserving food and water, the difference between protein and carbs, and so on, try to teach the rest of the class to follow their lead. But even that knowledge isn't enough to help when strange, aggressive mutant animals show up, and the crops are primarily foreign and alien, and sometimes even poisonous.
The difficulty of fighting against the animals, cultivating mutant crops, and staying alive in this future hellhole causes massive rifts among the children. Some of them insist they could become better leaders. Some kids leave and join with those who promise to do a better job. Many of the kids fight. Some steal food for themselves, only to be beaten or even killed by other kids for having done so. The younger grades are essentially entirely helpless, and a preschooler who happened to be visiting the school when it was transported into the future ends up being the ward of a few kids who try their best to take care of him.
Humanity is at its worst - and sometimes best - here, like it is in any tragedy. The depiction of the children's attempts at order breaking down from the chaos is sadly believable. There's no adult supervision, and many kids will simply not take orders from a kid who isn't doing a perfect job of keeping them safe. When brutality becomes the norm and most kids look out for number one, what ends up sticking out are the moments of compassion. The way some of the kids go out of their way to steal supplies needed to save another kid's life. The way many of the kids try to protect the preschooler. The way Sho cares for a handicapped classmate.
This is a brutal Coming Of Age
story, and perhaps a very realistic, dark look inside at loosely inhibited humanity.