Ever curious and happy to spend time with her mentor, Twilight Sparkle asks Princess Celestia about how the princesses created harmony in Equestria. The unicorn learns of the untold story of the alicorn sisters' struggle not only against Discord and his minions but also their struggle to get over their rivalry. Hearing both sides of the story, sprinkled between the ongoing antics of Celestia and Luna, Twilight has to decide for herself what to believe.