Cracked

Twilight Sparkle is the alicorn ruler of PonyVille. It's been years after the evil demon lord, Tirek's defeat, and peace has settled without interruption. Though time has taken its toll, and their sun queen, Celestia, is growing old. Soon, the sun queen may not be able to keep herself up. When the surface of Tartarus, a prison of the evil, cracks its gates open, all is unleashed. With the Griffins and Kirins constantly battling the ponies, it's impossible to completely have a clear view of the dark forces upon them. By the time Twilight and her friends find out what is going on, it would already be too late. The surface had cracked.