An Equestria of different kind, twist askew in space and time...
Caught betwixt the day and night, touched by both Sun and Moon light...

Princess Twilight Sparkle has returned, freed from her one thousand year imprisonment and purified of darkness thanks to Celestia and Luna, the new bearers of the ancient Mantle of the Heavens. Now, Princess Twilight seeks their help to undo the wrongs she inflicted on her sister in ancient times, and free Princess Rainbow Dash from her stellar banishment. Will the two sisters be able to reconcile? Or will old wounds run too deep?

An entry in the Reunions: A Swapped Roles Contest (in which it placed 3rd), set in an AU that sprung up fully formed in my mind under the tentative and slightly generic title of "World of Twilight".

Special thanks to ScatteredStarlight413, Neon Icy Wings, and Eikichirou.