Just a thought.??
1. The Dai Lee keeps a pretty strick watch over all new visitors that try to get to the king.?? However since they were busy trying to prevent the avatar from getting to the king in the first place then later trying to prevent the king from seeing the conspiracy, it is quite possible that Azula and crew got in unchallenged.?? They're trying to hide the war, surely the Dai Lee wouldn't let them near the king (of course they could have taken them out but oh well.)
2. Long Feng forms an alliance with Ozai's angels.?? "Place me as king, and I and my Dai Lee will help you." something to that effect.
3. Azula will make up a new plan.?? Katara is on her own in the city.?? Take her and Aang is sure to follow.?? However, Zuko finds out that little sister is in town and failed to come by and visit.?? Angry he goes to confront her, sees what she is trying to do and keeps Katara away from her.
RULES 1. Please no swearing. 2. place the number next to the theory that you discuss so we (mostly for me) can follow.


