Season 1 was exceptional one of the most emotional shows I've ever watch season 2 and season 3 (despite the annoying narration) for me were still very good but by the time we got to season 4 it was all a bit meh. Still had its moments but certainly a few levels below the rest. In summary season 1 10/10, season 2 9/10, season 3 8/10 and season 4 6/10.