Hotarubi no Mori e (蛍火の杜へ?) is a manga by Yuki Midorikawa and was adapted into an anime film in 2011. It has the same mangaka with Natsume’s Book of Friends.
This is a love story of a young girl named Hotaru who was lost in the forest that is inhabited by mountain spirits, and a human-looking spirit named, Gin. Gin was cursed ever since a child, he cannot be touched by a human otherwise he will vanished.
The story is sad, but it’s beautiful. I found this AMV in youtube and it happens to be one my favorite song “May I’ by Trading Yesterday.
SPOILER ALERT. ^_^
kixkillradio 
Thanks for the introduction! Love the art of it..story seems so whimsical and touching..=3
Yes, i cried after watching this. XD
If you like Natsume’s Book of Friends anime, maybe you’ll gonna love it too. 😉