On the wake of a nightmare, Twilight finds herself trapped in a strange and disturbing place with no explanation of how she got there. She has no memory of the night before, no understanding of how this could be. And she is not alone. Many ponies—mares and stallions, all around her age, have been taken from their homes by ponies who promise they are all part of something 'divine'.

She and the others are forced to participate in tests, both mental and physical, fight and run through brutal mazes. The only thing Twilight has to keep her mind together are the bonds she's managed to form with others and the hope that her friends will come to the rescue. But this place is far more sinister than she knows. Not until ponies are taken away for "Advanced Testing" does she realize just how hopeless her situation is.

Meanwhile, life in Ponyville goes on as always... as though Twilight had never existed at all.