A pony extremest bent on ending the rule of celestial and luna came to the gala with a perfect plain. Give the pink one super sugar rush inducing highly concentrated expresso. Shenanigans ensue.
The Doctor and Rose travel to the Crystal Empire only to find an arctic wasteland. The Doctor then finds an underground fortress that may be the cause of the Crystal Empire's disappearance.
1000 years ago Celestia, not Luna, went evil. She is slowly changing the land from a diarchy to a dictatorship. Luna is torn between bowing to her sister or fighting the one she loved most.