Sozin's Comet is only three days away. Zuko tells the others what the Fire Lord plans on the day of the comet and the gang realizes that they must stop him before then. But Aang doubts that he can do what is expected of him. Aang awakes on a mysterious island and confronts his past lives for advice on how to stop the Fire Lord without killing him. The rest of the group searches for Aang. Zuko battles his sister with Katara's help for the right to be named Fire Lord. Elsewhere, Aang meets Ozai just as the comet arrives. Aang's moment of truth arrives. Can he defeat Ozai, the Phoenix King? Will he be forced to take a human life? All the characters face their greatest challenges.