The twelfth (and final) episode of Anastasia's Magical Wish.
Mami and Homura, while watching Stacey become a witch, realize she's the first Puelian to become a witch, and that all of the other Puelians have gone back to their world if it seems as though they're defeated. They fight her, but Stacey breaks Mami's Soul Gem in the middle of the fight, killing her. Angry that she's the last Puella Magi left, Homura uses all of her powers to kill Stacey's witch, and Homura herself dies, too. The Puelian world becomes destoryed, with its people, now normal humans, scattered on Earth. Also, Tubey has disappeared, and witches still linger about. As Kyubey was about to set off to find girls to make contracts with, Christina stops him, saying that she wants to become a magical girl.
Soon-to-be Puella Magi