A mirror between worlds shattered. A girl driven mad by power ripping holes between worlds. A spiteful mare traveling through time to get revenge. When the fabric of reality surrounding Equestria starts to come unraveled, it falls to Twilight to find a way to fix things.

Good thing she has a familiar face to help her. Several of that face, actually. An alicorn princess (canon Equestria), a human mechanical genius (Equestria Girls), a brilliant but irritable slacker of a unicorn (Reflections), a stallion no less intelligent or magically gifted than the rest (genderbent Equestria), and even a unicorn obsessed with Dark Magic, working together to save all of their worlds, by returning Harmony to the world they find themselves in.

A world where Nightmare Moon rules Equestria after sealing Celestia in the Moon, only to go to war with the Crystal Empire, against King Sombra and his Umbrum army. A world where Discord wrought havoc, until his powers were stolen by Lord Tirek, who rampages across both sides of the war indiscriminately. A world where even the ponies far from the fighting must constantly fear Changeling attacks. A world where Harmony is nothing but an empty dream.

A world where Twilight Sparkle never existed.

What could possibly go wrong?

Contains spoilers for the cartoon, comics, and movies.