On secret assignment from Princess Celestia herself, Twilight investigates a powerful magical artifact for clues to the mystery of Luna's transformation in the evil Nightmare Moon. Incautious use of the artifact sends Twilight hurtling back in time. Can Twilight discover what caused Luna's transformation? And will she ever make it home again?

Kickass cover art used with permission from Bitz.
http://allthebitz.tumblr.com/

A terrible affliction has befallen the peaceful town of Ponyville, and the lavender unicorn and her friends are right in the middle of it! And the edges of it. Heck, it's pretty much lavender unicorns all over.

A story unrelated to anything.

Immediately following the events of Appletheosis, Applejack must relearn her place in the world as the new Princess Mara of Equestria. Meanwhile, her family and friends have their own troubles with the changes. Through it all, little Merry May, first in the service of her goddess, tries to hold things together and keep everypony sane and happy.

I won't tell you what to do, (this time) but reading Appletheosis first is highly recommended. The Shadow of the Goddess also provides useful background and will become very relevant in later chapters.