There will be spoilers, and you might want to start with part one.
Keep in mind that this is just a fanfiction, and that Azula's thoughts and scenes in between Sozin's comet never happened.
Azula was still thinking. He won't deny me, I'm the Princess! I'll get it out of my head, what to say, what to say...?
Then she spoke: "Sorry I'm late, father. Good palanquin bearers are so hard to come by these days. So, is everything ready for our departure?"
Then she heard the words that made her die a little inside. No, not a little, a lot.
"There has been a change of plans, Azula."
It can still be good. Azula thought, The change of plans could be that we're attacking the water tribe too. Or that my mother really cared about me.
No, that would never happen.
"I've decided to lead the fleet of airships to Ba Sing Se alone. You will remain here in the Fire Nation." Ozai told Azula.