Ashita no Kioku
As Sho said in a recent interview, it depends on the person of what feelings they'll feel from this song, because that's what he noticed comparing his opinion with the other members.
For me, when I first watched the pv I got the feeling of sadness and loneliness, recently I feel some sort of hope when it starts, but it's still mostly sad. I love it by way, it's very beautiful.
Enjoy the pv. They look gorgeous.