When Twilight Sparkle comes back to Canterlot for a few days, she stumbles upon a legend she's never seen before.

A legend of an island far to the west of Equestria, surrounded by a perpetual storm. Many ships have been lost in that area with few survivors.

Those who do say the same thing. The island is a lost world. A window to a past that is long forgotten.

In time, that past will return and shake the foundations of Equus.

A war is coming, and Equus will be forever changed.