In a world full of magic, mere words can pose a deadly threat. When simply reading a sign can instantly infect the unwary, and cases start to turn up all around Ponyville, Twilight Sparkle casts the only spell she can find that can give her the time she needs to find the cause of the plague. But then she has to figure out how to stop the epidemic... without being able to read.

Editing provided by Spabble
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Audiobook on YouTube and for download on SoundCloud
Spanish version translated by MIkimoco
Russian version

Many years after sending her beloved protege to Ponyville, unease sits heavily on Princess Celestia's heart as her relationship with Twilight Sparkle seems to have cooled despite all they've accomplished together. On the advice of her sister, Celestia sets out to investigate and resolve the lost connection with her most faithful student. What does it mean to be a Faithful Student...or a Princess of the Sun?

Earned a six-star rating on Equestria Daily and featured on its very own TVTropes page!.

Princess Celestia tires of constantly being surrounded by decorum, deference, and formality, and decides to take a day off from being Princess. But visiting Ponyville incognito is harder than she expects. Will she be able to fit in and make friends without blowing her cover?

It's been a few weeks since Luna's returned from the moon, and all is not well. She's become more introverted than ever, rarely leaving her room and obsessing over work. Celestia hopes that studying Twilight Sparkle's Friendship Reports will at least help her get out of her shell, though an unusually talkative servant may just help in that regard...and is anypony else getting strange feelings from that statue out in the gardens?

As of May 4th, now featured on Equestria Daily. *Squee*

Luna has had enough of Celestia's games, and has found the perfect means of revenge. Using a long-forbidden spell, she transforms her sister into little more than a small filly, all so she could pull the greatest prank ever. Unfortunately, she soon learns that before you fool around with dangerous magic, you really need to read the fine print...

A sequel can be found here.