Princess Tutu unfolds like a fairy tale brought to life, centering on the clumsy, sweet, and gentle Ahiru, an unlikely heroine in a town filled with talking cats and crocodiles. In truth, Ahiru is not human at all: she really is a duck, transformed into a human girl by the mysterious Drosselmeyer. Once she learns the reason for her existence, she begins to understand the strange place she occupies in this story and the burden that comes with it.
With her magical egg-shaped pendant, Ahiru can become Princess Tutu, a beautiful and talented ballet dancer whose dances relieve people of the turmoil in their hearts. Guided by that power, she takes on the task of gathering the lost shards of her prince's heart, fragments scattered long ago when he shattered it to seal an evil raven away for all eternity. Princess Tutu follows heroes struggling against fate, where beliefs, feelings, and actions shape the outcome of the tale itself. In the end, the story asks whether this fairy tale can still reach its promised "happily ever after" on the strength of its characters alone.