Duck awakes from a dream in which she is a duckling, watching a handsome prince dance ballet. Later, she walks early into class and discovers Mytho, an advanced class student, dancing alone. When she trips, he dives to catch her, twisting his ankle in the process. Duck wants to apologize to him but is prevented from doing so by Mytho's controlling roommate, Fakir. The next morning, Duck resolves to apologize to Mytho, and spies canary chicks beginning to fly. One of the hatchlings hesitates and is forced to jump when a crow tries to attack it. Mytho leaps to catch it and falls as well. To save him, Duck transforms into Princess Tutu. Mytho asks who she is. Tutu/Duck remembers that she is a duck, and runs away.

The next day, Duck wakes up to realize that she is just a duck. Drosselmeyer appears to tell her that she is also the legendary Princess Tutu; her task is to return the pieces of heart to the Prince, Mytho. Longing to one day see Mytho smile, she decides to take up the challenge. Drosselmeyer gives back the pendant that changes her into a girl, as well as Princess Tutu.\n\nAn Anteater-girl, who is bitter and jealous of Rue for her superior dancing skills, sets her eyes on Mytho. She and Mytho have a dance-off with Rue. Rue chooses Duck as her partner and they win. Duck discovers that the anteater is being influenced by a shard of Mytho's heart—the feeling of bitterness. She transforms into Princess Tutu and convinces the heart shard to return to him. Mytho regains a feeling, which worries Fakir.