Twilight Sparkle took Starlight Glimmer under her wing and offered to teach her the ways of friendship. Starlight was a truly precocious student, exceeding Twilight's expectations every step of the way. Now, a mere year after becoming her protege, Starlight has achieved that which took Twilight since fillyhood: She has ascended and become an alicorn princess.
However, when Starlight begins to question what this means for her dreams of an Equestria where everypony can look upon each other as equals, Twilight realizes that she may have made a grave mistake.
Cover art by Lunarina, used with permission: http://lunarina.deviantart.com/art/Princess-of-equality-525178614