Running low on pages to talk across the dimensional rift, Twilight reads what might be Sunset’s final message to her. However much to Twilight’s surprise, there’s also another message to a different pony.
Starlight Glimmer is what you might call a problem teenager, and her peer mentor, Sunset Shimmer, doesn't know what to do with her. Until she comes up with the one person who might be able to understand Starlight: herself.