When the powerful and mighty Discord is defeated by the Six Elements of Harmony, the ponies of Equestria thought that his second incarceration meant the end to his chaos. However, his final hurrah has not yet been given. For the Element of Chaos does not believe in leaving the party without one last, great prank.
Now, as Twilight Sparkle faces dreams in darkness, and portents of doom and gloom arise, the Elements of Harmony as well as everypony else in Equestria must prepare for the biggest problem they've yet faced. No mere princess to be freed from the influence of darkness, or the imprisonment of the embodiment of Chaos, this is bigger than anything before.
For as events unfold, a race long thought mystical and legendary on Equestria is coming back...from another world. As the greatest minds and leaders of the Edwardian age are confronted with the fact that humans are not alone in the universe, Twilight and friends must deal with a world so very different from their own. Where magic is merely the application of sufficiently advanced science, and where Friendship and Harmony are sorely lacking.
Now the history of Earth and Equestria are forever altered as the forces of harmony and friendship explore a world of industrialization and war, where both sides have some things to share, for better and worse....
