(EDIT: Slight grammar edits to make the story more smooth.)
Discord stood above a high mountain top above Equestria, and the mane six have been turned to stone. Now Princes Celestia must find six new heroes/heroines to defeat him.

But who will step up to the challenge?...Could it be...Uncle Grandpa? Spongebob? Maybe even Riley and Huey Freeman? Who knows, all we know is this: Things. Will. Get. Funky.

Warning: Again, everyone but Discord, and the replacements are anthro.