I was really wondering where could it end but I did not expect the outcome. Now I feel that it was determined to have this ending :D
For me what was very beautiful that everything which they accomplished they did it for one thing. We can say that this is boring and has been used many times but as I said already you probably cannot understand how strong the bond can be between parent and child. It looks like it is strong enough to even change the world.
I loved the whole concept and I agree that it was painfully slow sometimes but in my case it only made the ending more convincing.
Probably not a 10 points series but currently I am so amazed that I must give it a 10!