At the end of OOO, Eiji Hino successfully defeats the Maki Kyoryu Greeed, sending the Core Medals through a black void, and watches as his friend Ankh passes on, before leaving for another trip to find a way to revive Ankh....

This is not that story.

After defeating the Kyoryu Greeed, Eiji is sucked into the void along with the Core Medals and wakes up on the other side in the world of Equestria. Quickly taken in by Twilight Sparkle and the rest of the mane cast, Eiji is found the centre of attention for Ponyville, whose citizens are fascinated by this strange 'human' creature.

At the same time, the intrepid and adventurous Keyblade Wielder Sora finds himself sent to Equestria on a mission of dire importance. Upon the arrival of these two strangers, Equestria finds itself besieged by a horde of violent monsters, the Nightmares, conjured and controlled by strange pony known only as Entropy, who claims to serve a being he only refers to as "Majesty".

Now, Sora, Eiji, Twilight, and her friends must band together in order to defeat Entropy and his fiendish creations, and prevent them from destroying Equestria and the balance of harmony in the universe.