In the aftermath of the Blackest Night and facing the Rise Of The Third Army, the Entities of the Emotional Spectrum powering the various corps fear for their existence. As a precaution, they put a piece of their essence into special rings and cast them into another dimension; the world of Equestria.
However, the Black has also found Equestria and begins another Black Lantern invasion. As the prime rings find their new hosts, they must fight against an onslaught of undead terrors...and perhaps even each other.