Two worlds, Equestria and Earth, become more and more alike. Earth has been destroyed by nuclear bombs, making life in the radiation-filled dystopia a struggle. But life in Equestria too, becomes bleak and terrifying, as the changelings launch a new invasion, and finally succeed in bringing Equestria to its knees.

The elements of harmony have been lost and scattered, teleported to a new and horrible world. Together, Twilight and her friends have to tread the radioactive face of Earth to find the elements that have been lost and defeat Queen Chrysalis. Luckily--or unluckily-- they receive help from a very strange pony, a pony who came from Equestria, but has been shaped to fight in the brutal war on earth that still goes on to this very day. His name is Triggerhoof.