Princess Twilight Sparkle is the Princess of Friendship. As such, she uses her position to spread friendship throughout the land of Equestria. This is knowledge that everypony knows.

But when a powerful enemy takes advantage of Twilight's friendly nature and attack the peaceful town of Ponyville, things seem pretty bleak. In a last ditch effort, Twilight mails Celestia one last letter in a desperate bid to save a few lives.