(This story is sci-fi, and somewhat different to regular FIM stories.)
Aneki's world was small. It was spherical, and it only took a day to gallop from one side to the other. She had been taught nothing existed outside the sphere, but she wasn't so sure about that. Perhaps her world was a bottle, a container in which ponies had fled to live. A time would come when she gained the opportunity to investigate these things first hoof, if she lived that long.

One day, Twilight Sparkle discovers something amazing about her friend Sunset Shimmer.

She's a magical talking pony!

This requires investigation! Science! Possibly a full-body physical!

Or maybe Twilight will just ask her what's up with that.

Rated Teen for frank discussions about... y'know.

Sunset Shimmer visits Equestria and spends some time taking care of animals with Fluttershy and Rainbow Dash.

Rainbow Dash is apparently not good with certain animals.

Sunset discovers very quickly that what you learn from the human world cannot be unlearned, ever.

Rated Teen and Sex for a pile of juvenile innuendo, though technically no bad language. Only technically.

Sunset Shimmer loans Pinkie Pie a thumb drive.

Except that it's the wrong thumb drive. And that it contains exactly what you'd expect to find in the wrong thumb drive to loan away.

Rated Teen and Sex for discussions of pornography and self-love.

Twilight breaks into Starlight’s room to figure out why she locked it.

Now she’s in, and regretting every second of it.

Reading by Steven1992 and Scribbler!

Well it's not actually a sequel. Here is a collection of short stories and histories detailing the life of Alternia, a changeling queen impersonating the life of Princess Celestia. These are the stories of the ruler under her mask.

Reading the main story: Princess Celestia: The Changeling Queen is a requirement if you don't want to be spoiled or confused. I will try to provide background information when I can.

For readers of the main story, there are basically no spoilers if you've read past chapter 8. Enjoy!