I agree...I don't understand why they had Zuko ask about his mother if they didn't even show her or have any follow up on that....

that's why i still think there might be hope for a book four, but i still doubt it...
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Azula dies. She wasn't in prison and she was no longer mentioned.

well, they might make another season about Zuko finding his mom.

hmm....good point

How would you know that She Died? Sure She went Completely Insane and Probably was Suicidal. But you can't tell for sure.

I know because she wasn't in the prison and nobody ever mentioned her alive again.

I'd really like to know what they did with that nut case! I want to know what happened to Ursa too! All of this is drivin' me crazy!!

I think Azula died of craziness. I don't know for sure.

Zuko's mother was banished and it is never said exactly where she is though we can guess that she is still alive. After Katara captured Azula she was put in a mental health facility where she was closely guarded...
I feel like I should say more... my answer feel so much like a dictionary definition with out any life in it! :(