Queen Chrysalis has trusted her son, Prince Pronotum, with a very important mission to Ponyville. He is to infiltrate the town, find a way to remove the Elements of Harmony from the picture, and prepare for a second invasion. He's determined to make her proud. Unfortunately for Chrysalis, her son isn't very bright, and, as a result, he took a few months too long to get to Ponyville.
UPDATE: Glorious cover art by GIULIO.