The song is about a japanese story, and the story is about the sun goddess, Amaterasu. Here, watch it for yourself!
https://www.youtube.com/watch?v=2nA0wuJSxlg
I always end up feeling better after to this song, even if I wasn't all that down beforehand.
On a slightly darker (for lack of a better word) note, it took me a while to find something that looked a little Japanese for her to wear. '-_- Sorry. Just pretend the blanket and the tank-top are one piece of clothing. The little eggy person is another god/goddess, trying to cheer Amaterasu up!