A failed space flight kickstarts a chain of events leading Twilight Sparkle and her friends to become embroiled in a war that will decide the fate of all of reality.
In the blink of an eye, all life was wiped from the face of Equus by an abomination born of the stars. That is, all except for four immortal Princesses. Now they fight for the only thing they have left other than their grief... revenge.