What happens to a man who goes to war? He fights for the ones he loves. What happens to a man who goes to Equestria, and goes to war? He does the same. The only difference: In a world where there is no such thing as war, it becomes so much worse.

Our young hero goes off to war, and quickly befriends a young Alicorn prince of a foreign nation. What will happen when the two are placed into what is, perhaps, the absolute worst possible situation together?

And meanwhile, back in Equestria, will Luna's grief of being separated from her beloved overwhelm her and make her change into the worst 'her' there has ever been?

SPOILER ALERT

Nightmare Moon!