Twilight Sparkle has accidentally shattered the magical mirror. The mirror isn't completely broken, but enough to be noticeable.

So what does she do? She gets her friends to help her put it back together. When they're done, Pinkie suggests that they try it to test and see if it still works properly.

It still works, no doubt, but where they land is the predicament.

So what happens when they are falling for the ones they meet in the world? Something unpredictable.