There's an old saying among ponies: Be careful what you wish for, because you just might get it.

In the aftermath of Tirek's rampage, Celestia finds herself thinking upon her life and yearns for those moments of glory and adoration from her youth. While on a trip to the Crystal Empire to assist Cadance and the other princesses in repairing the damage done by Tirek, Celestia finds herself drawn through the magic mirror into another world. Stuck with no way to return or communicate, she is forced to rely on the kindness of her newfound allies. But even here, dark shadows loom that threaten all...

Twilight and the other Elements of Harmony have saved the land of Equestria from Nightmare Moon, Discord, and the Changeling army, but now they face perhaps their biggest challenge yet. A challenge that lurks behind smiling faces and friendly eyes. A challenge that threatens to overtake the entirety of Equestria and enslave its inhabitants. But the ponies won’t face this threat alone. Help comes in the form of the most unlikely of companions: four teenagers, a hawk, and a blue centaur.

Canterlot vanishes in a mysterious explosion, an explosion which engulfs all of Equestria. Twilight manages to save herself, but the world she finds herself in is not the one she remembers. Her friends have no memory of her, the world is trapped in darkness, and Celestia is missing. Can Twilight figure out what's happened to her and the rest of Equestria before the darkness overwhelms her?