Before Celestia banished Nightmare Moon for 1000 years, a rift between the Royal Sisters had long been forming. This is the story of that rift, and the devastating effects it had on The Two and other ponies of the time.

To date, two facts are well-known: Celestia banished Nightmare Moon to the Moon for 1000 years; and Luna was trapped inside of Nightmare Moon, fully aware of the monster she'd become and completely helpless to do anything about it.