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 can get anything you ever wanted.
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.