Equestria is in grave danger. Celestia is dying under a curse. A special artifact must be found to save her. Meanwhile, the greatest threats in equestrian history have returned. Princess Cadance is pregnant with a foal, and is in no less danger than the Crystal Empire is as well. King Sombra, Discord, Nightmare Moon, and Queen Chrysalis are all back, demanding the things they were after in the first place. The elements are gone, and there is nopony that can trust anypony.