(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.

Lazy Pines is a small town in the high country of Colorado, easily overshadowed by the bigger sights to see along Colorado State 9. When influenza strikes the town hard, it is little more than a statistical blip in a typical flu season. No one thinks any more of it as the initial wave of infection passes ... until the other symptoms begin to manifest.

Meanwhile, during what should have been a routine trip to Canterlot, Twilight Sparkle stumbles upon a strange anomaly which turns into an all-consuming mystery. As she discovers the complex web of magic stubbornly maintaining this mystery's secrets, she grows worried what it could mean for herself and her family.

And as the residents of Lazy Pines struggle to understand -- or even believe -- what is happening to them, two worlds have irrevocably been set on a direct collision course.

Updates every other weekend.

Cover art by Mix-up. Please check out more artwork by this talented artist.

Now has its own TV Tropes page thanks to redandready45.

Sunset always knew that she was destined for greatness, but she never dreamed of how great she could become. Not until she had seen it – the mirror had shown her as an alicorn. Ignoring Celestia’s warnings, Sunset goes looking for answers.

When she learns that the mirror is also a portal to another world, well, what else was she supposed to do? But it seems that she hadn’t considered every possibility. She hadn’t, for example, considered that she might get herself trapped on the other side. Nor did she think she’d find herself transformed into a child again.

(Also available in print (temporarily out of stock), as an audiobook, and in Russian!)

A story set in the Who We Become series (earliest story, so a great starting point )

Many muches of thanks go out to ArchAngelsWings, Dessert, Mind Jack, Pasu-Chan,
CharCharChan, w_brown7, and eton975 for proofreading.
Additionally, thanks to Pasu-Chan for providing the glorious cover art