After taking the wrong mirror and landing in the human world, our hero finds himself in a world even his Equestrian friends don't fully understand. While there, he meets a few certain villains nobody has seen for a long time, and they're as bad as ever. They found a way to restore their dark magic, and once again seek to enslave Canterlot High. Will Diamond be able to beat them at their own game? Or will they get the better of him?