When the Great and Powerful Trixie manages to vanquish an Ursa Minor rampaging through Ponyville, Twilight Sparkle finds herself with a ruined reputation. And as Trixie continues to gain in popularity, Twilight finds herself more and more alone.
Revenge may seem like the only available option, but maybe there are more things going on than it seems...
Addenum: No, this is not in any way a Twilight-bashing story. Please read before you make up your mind.