Equestria's weather is controlled by the pegasi. A problem, however, is the mist that covers up the towns from Appaloosa to Manehattan. to the ponies, it is but a cloud that is weighed down, just like fog. However, none of the pegasi can tame the mist that continues to expand over Equestria. In fear of what might happen to not only ships that would sail through the blinding mist, but to Equestria In general, Twilight Sparkle and her friends will have to figure out who/what is doing this, and why they do it.

(Disclaimer: This has nothing to do with the World of Warcraft Mistweavers.)