During a trip to Ponyville and after a trip to Sugarcube Corner, Celestia suddenly gets a horrible toothache. She is very apprehensive about going to the dentist but Twilight ultimately persuades her to go. To ease Celestia's pain, Twilight suggests that the dentist write a spell to remove the pain involving root canals. The result benefits more than just Celestia.

This story is of how Fluttershy has so much rage and frustration built up within her that she transforms into a wrathful pony named Brevity Thrash. She turns from being a sweet pegasus into a vengeful and violent Alicorn. There is little her friends can do to stop her but in the end, the most unlikely of all characters is the one who reminds her of who she really is and causes her to transform back to being good.