Equestria faces great peril. Luna has gone missing, and for some reason neither Celestia or anypony else can raise the moon. And if the moon does not rise, then magic will all but disappear from the world.

To find the missing princess, Twilight and her friends travel to new lands so very different from their own. But what they find there will challenge everything they believed to be true, and could very well be the beginning of the end of the world as they know it.

Note: This diverts from the series after season three, so technically speaking, it is AU, although I have not tagged it as such.