You know how in the 2nd episode of Book 1, Katara screams for Aang when she sees him fall into the water and not come back up? How his love for her, and the understanding that she needs him, triggers the Avatar State and Raava brings him back to her?

But do you know what I hear and imagine besides that? I hear a 68-year-old Katara holding onto Aang's lifeless body, desperately screaming for her husband's name louder and louder, even though she knows he's gone. And this time, he ain't coming back.

Step 1: Prepare for battle