Inspired by the artwork A Royal Picnic by ShutterflyEQD
Set after Season 7 Episode 10- A Royal Problem
After a mission well done, Princess Celestia invites Starlight for breakfast before she and Twilight leave for Ponyville. Starlight, finally out of Twilight's questioning has a chat with Twilight's own long-time teacher. They find that both teachers have a lot in common, and turns out that the student and teacher are more alike than Starlight thought.
Going for a nice, easy-going one-to-one character story for this.