I’m sorry I can’t give any details but I just remember I once saw an Anime series I would like to have a look at again.

I think it was about a (future) earth where the earth was suddenly surrounded by a kind of energy sphere in the sky. I remember it was blocking everything so they couldn’t leave the planet any more or something like that.

And it was a kind of mirror / alternate world or something like that “up there”. I know that sounds like that “Upside-Down” movie from 2012 but I’m sure it was an anime (and most likely a series and not a movie) and should be slightly older than that. But it wasn’t really old. I remember it looked already CGI enhanced so I’d say early 2000s.

I remember a dark, sad mood like it was changing the world to the worse not better. If I would have to guess I’d say the (english) title was something like “Twin X” or something abstract like that. Maybe containing “sky” or “mirror” in the name?

Does anyone have any idea which one I mean?

Thanks for the help!