Two unicorn twins, Fortune Flicker and Lucky Luster, have been destined since birth to wield the Keyblade. After instructing the ponies in Canterlot Castle for fourteen years, and with a threat of Heartless yet to appear, Princess Celestia sends them to Ponyville to study magic under Twilight Sparkle, both to expand upon the twins' abilities and their experiences, and to introduce Twilight to the magic of teaching. But when an ancient villain appears, commanding an army of Heartless, will Fortune and Lucky be able to save Equestria - and the rest of the world - from descent into darkness?

If you're worrying that I'm going to break characters by introducing Kingdom Hearts characters into the pony universe, don't. There won't be any Kingdom Hearts characters in this story, except for the Heartless, and there won't be any traveling between worlds. Given the option, I wouldn't even even call it a proper crossover. It's more like the Kingdom Hearts mythology applied to the MLP universe.