I know, what you mean, it was quite popular and it was playing at nights on alternative hour show. I would even say, it is older than 4 years...
Sorry, I'm very bad with remembering videos, but I think, she run into some kind of a shed, and in that shed she met her twin?...
And if i recall now right; when she was running outside, the video had a few men in there also, possibly players from the same band?
I also remember, it was little bit more upbeat than usual Air, I mean, there was a little more beat, but it was definitely not a dance song. It was a mellow one. (ohh my stupid English skills, I hope you get what i try to say

)
Sorry, this is all i remember, but maybe this will help? (i doubt it, but let's hope)