Rarity discovers that she is a very rare kind of pony; a Marshmallow pony, which are born only once every millenium. But some strange ponies appear attempting to capture her, and so Rarity must escape with all who know her secret.
When two unlikely ponies, Luna and Sombra, meet beneath the silver moon, will their love be everlasting, or will the darkness lurking in the Crystal Empire succeed in destroying them?