Tower of god is about a boy who has spent all his life trapped in a cave - like he belonged there. Until a girl finds him and she becomes his best friend. One day she tells him she won't be coming back because she is going to climb a tower, and if you climb to the top you get a wish.
He leaves the cave and chases after her and climbs the tower to try and find her.
This has to be my favorite manga period next to the 7 seeds. It starts off a little slow but once the supporting characters come in it is amazing and when part 2 started it was a breathe of fresh while sticking to the characters.