For every living being in Equestria there is another of them in another world. Visually, they could pass for identical twins (if they were in the same universe, of course) and both versions often have a lot in common, but the worlds operate differently. Everypony and every human could be living vastly different lives.

Starlight Glimmer learns about all of this firsthand when a mysterious letter comes through the mirror asking for her help signed by the other Starlight Glimmer. The only way to figure out how to help her is to take her place in the human world and keep an eye on everybody who would want to harm her.

Can she figure out what happened to the other Starlight before it becomes her fate as well?

Can the redeemed Starlight fix her counterpart's mistakes before she goes down a dark path?

And why does Sunset Shimmer act so strange whenever Starlight asks her about the human Sunset Shimmer? Or Equestria in general?

*Written for National Pony Writing Month*