Overview
This anime is set in an post apocalyptic era where almost every humanity is finished.
But rather than regular anime where people get powers and fight monster etc. this anime is little different.
Also Here we follow 2 different stories happening simultaneously.
1)First is set in a lab which far from any disaster and in a closed peaceful environment where orphan children are raised. But there is an very dark plot happening behind in name of orphanage.

2)Here we follow 2 of our main character who have their own tragic backstory where their goal is to find a certain person while encountering dangerous entities.

Why to watch
*The story is very interesting and unique
*It has amazing world building
*It is an survival/mystery story is fascinating
*The animation is top notch
*Has 13 episodes

Why not to watch
*There's only one reason, that S2 is not announced.

Overall Rating:- 8.5/10