Everyone in Equestria is having a Magic Festival until trouble arises when they find out that the Elements of Harmony are missing. The Mane Six have to find out who's behind it and put a stop to the culprit. Meanwhile, the culprit is revealed to be a new villain named Sid who tries to use the Elements of Harmony for his nefarious and notorious purposes in secret.
Now let's pretend that the Elements of Harmony aren't shattered, and that the Mane Six still haven't had an arch-enemy yet (I don't mean Discord because he's reformed). Are you ready? Okay.