Twilight awakes from troubled sleep to chaos- parts of Equestria itself are simply missing, ponies have vanished overnight. Twilight has no answers, but Celestia must surely know. The unicorn must gather her scattered friends and delve deep into the history of her world and perhaps into the history and mind of Celestia, her beloved teacher. What hides in the misty and unclear accounts of Equestria's early history, and why is it only now rearing its ugly head? Twilight has to know, and her world needs her to know, because no one else can stop the tides of chaos and darkness.