The universe is comprised of several dimensions - some spacial, some temporal, some even ethereal. These dimensions keep the universe running, and allow its mechanics to stay running smoothly. They're usually thought of as a fabric - a gigantic patchwork of various unimaginable concepts.
What happens, however, when a certain violet bookworm tampers with the patchwork? What happens when the dimensional balance is disrupted, causing things to fall out of order?
Everything falls apart.
Twilight Sparkle, the favoured librarian of Ponyville, and thrice saviour of Equestria, destroys the universe. And no one is particularly pleased about it.