The kids think only their parents aren't good enough, thinking they'll find some better parents out there, when in reality lots of kids think like this.
Oh my god.
So
The whole plot is something like :Someone brain washed all the kids to murder their parents/guardians
and the whole country or atleast the selected area is killing their parents just like they were instructed to.
Well why i believe its something like brainwashing?
Because every kid that is running away has burned their houses in the same fashion as well (probably)
