“Once upon a time, a man died. His work was creating stories to tell other people. In defiance of his death, in his last story was a brave and beautiful Prince, who was supposed to defeat a monster Raven.
“However, now there would never be a conclusion to their endless fight.
“‘I hate this!’ screamed the monster Raven.
“‘I hate this!’ screamed the brave Prince.
“The monster Raven flew out of the story, and the Prince ran after it. And then the Prince took out his own heart. Using a forbidden power, he sealed away the monster Raven. At the same time, ‘Dark!’, came a muttering from somewhere from a man who should have been dead.”
Princess Tutu is about ballet, and fairy-tales, Princes, storytelling, and the girl in the class who is the ugly duckling.
Which means this is a descent into a metafictional maelstrom, as well as being a sort of Utena-lite, without the sexuality (except in the guise of the marriage-obsessed Neko-sensei). And that it can draw upon the wealth of classical music for its sound-track.
Hell yeah! I'm watching an anime for little girls! -- It's that good!