After five years of renewing the world from the scars left by Ozai's reign, you'd think Katara could catch a little break when she visits her friends on Ember Island for a summer vacation. But one night, Katara has a chilling vision of strange people clustering around her, and an old woman telling her that the Avatress is rising. People have mixed feelings about it, but their all asking the same question: Who is Avatress?
Now, Katara is thrown into a heart pounding, soul searching race against the clock to find the dying source of both the Avatar and the Avatress's powers, but there is only one catch: She can't tell anybody, not even Aang!