Discord's power was something that always frustrated Twilight. All that power, with no effort, no cost. So when Discord offers her a chance to learn his secrets, Twilight quickly agrees. Unfortunatly all things come with a price.
Twilight has theorized the possibility of creating pocket dimensions. Facing the ridicule of the theoretical magic community she has set forth to prove them wrong. She constructs a portal and enters it. Inside, she finds a field of empty white.