This story is a sequel to A Sunlit Night
Young Sunset Shimmer has just learned of Celestia's sister after being accepted as her personal understudy for her great magical prowess. However, has Sunset already met the Princess of the Night without knowing it or is it somepony else who calls Celestia her "dear sister?"
It is not necessary to read A Sunlit Night before this one as this is its prequel, but you will most likely find it far more enjoyable.
Takes place before A Sunlit Night and focuses around the flashback of when Sunset was still rather young and had received her cutie mark. I know some of you wanted to know more about how Sunset knew of Luna even though she would still be banished to the moon during this time period. It will cover Sunset's life from when she was in grade school up to when she becomes Celestia's pupil.
FYI: The artwork belongs to me so don't worry about the source.