A strange alicorn named Cosmic has been found near the Everfree Forest. Twilight and her friends are unsure of what to do when she tells them she is from an alternate universe called Enigma, and asks them to come to her homeworld and save her kingdom. Under Celestia's advice, they go…yet this world is more dangerous than any of the lands they have faced before, and who is the real enemy? The Boggons or Princess Cosmic?