Following a strange retreat, King Sombra has summoned Princess Cadence to a secluded room in the Crystal Palace. There, he warns her of the most dangerous creature to ever walk the face of Equestria. They are many. They are strong. They cannot be trifled with. One arose, thousands of years ago, and wanted nothing more than to see the world at her mercy. And, through sheer chance, Sombra finds himself alone and aloof in a maze of ruin, fighting for something even he cannot name.
What happened to the Crystal Empire?