Princess Celestia understands that being an Element of Harmony is dangerous, and that Twilight and her friends are bound to make enemies. So, naturally, the only course of action is to send a guard to keep them safe, even if they don't know about it.
Stray magic is running rampant through Canterlot City and people affected by it turn into dangerous monsters. But through the use of an ancient family heirloom a new hero tries to save the city.
When the Multiverse is in danger, Twilight, Spike and Starlight must team up Sunset and some other heroes from the worlds to help save it from the evil Alliance of Darkness.