The meteors have already rained on Equestria, destroying the home the ponies once knew, starting with Canterlot itself. The Seethers, a wretched parasite hidden aboard the rocks like a stowaway plague, stripped the land of what the ash and fire could not. What paradise was there is no longer. There is now only the Black Lands of the old Equestria.

But that's all in the past. Years later, what ponies remain struggle to rebuild on the fringes of the world they once knew. Some try to take refuge in the wastelands the Seethers won't touch, while still others won't feel safe until they've gone as far as the lands of the other races of their world. A select few stand watch at the edge of the safe world, keeping stragglers at bay so other ponies may lead peaceful lives. These guardians call themselves the Equestrian Guard.

For the longest time, even the Guard had given up hope of ever seeing their old home again. From the safety of the desert mesas, they could see just how bleak the horizons were. But strange events are beginning to unfold; a new kind of alien falls from the sky, old faces thought long dead resurface from the rock, and an ancient power presents an ultimatum. The ponies may not realize it, but they do still have a chance to reclaim their home and save their planet. Their fate simply resides in the hands of a child, a pair of scouts, a changeling, and the old heroes of the dead world.