Devastation

When a certain someone sneaks up on the gaang they have to fight. The gaang is sleeping, then suddenly Azula comes and tries to take justice for her father by taking the one thing Aang loves the most Katara... What will happen to Katara? What would Azula do to get Aang to join her and restore her father's bending? Will Aang sacrifice himself to save Katara? Or will it be the other way around?