A storm that cannot be cleared looms over Equestria. Twilight, Spike, Fluttershy, Rarity, Applejack, Pinkie Pie, and Rainbow Dash are set into motion to figure out why. But as the friends search for answers, a mysterious fog overcomes four of them. The nature of Twilight, Fluttershy, and Spike's search changes from one of curiosity and prevention to one of salvation and intervention. The outcome of their search for answers could result in the end of not only their friendships, but of Equestria itself.