AU where Zuko figures out early into the series that his father is an abusive cockhead who doesn’t care for him and that the Avatar is the best shot the world has of restoring peace, but because Zuko is a stubborn, emotionally pent-up teenager he refuses to acknowledge this and officially sever ties with the Fire Nation. So he ends up not-so-subtly helping Team Avatar while pretending to still be on the hunt for said Avatar
This ends up with Zuko constantly running around as the Blue Spirit. Do you think people will notice that the Blue Spirit only shows up near places close to where Prince Zuko’s ship is docked? …. Nah
The crew is kind of creeped out by this version of Zuko that’s mellowing out and even occasionally smiling at nothing, even if he still has (strangely timed) moments of stress. The Avatar just slips through their fingers and the crewmen immediately around Zuko start scrambling away, expecting the prince to blow up, but Zuko just shrugs with this weird little smile and says, “What can you do?” And trots away to practice basic-level firebending. There’s a ship-wide bet going on about this. The most popular theory is that Zuko has straight up been possessed by a spirit. The second is just “puberty.”
Zuko also ends up “sneaking” various members of Team Avatar onto the ship to hide them/give them medical aid or food/have whispered conversations about strategy and mission plans. Half the crew are convinced that Zuko is becoming a rebellious teenager (in the conventional meaning of the word, not the actual rebellion that Zuko is cooking up) and is having his hoe phase and that’s why you can sometimes hear the whispered voices of young men and women coming from his locked room. The other half of the crew still kind of see Zuko as that bratty 13yo they first met and do not even want to consider the prince having anything even resembling a hoe phase
Meanwhile, Iroh knows full well what Zuko is doing. He’s probably helped more than one member of Team Avatar sneak off board by distracting ship personale and “forgetting” to leave certain doors locked. He’s going let his nephew bring up the subject to him in due time. For now, he continues pretending to be oblivious every time Zuko sneaks off board to help the Avatar firebend or get caught up in the gaang’s shenanigans of the week, and is quietly brimming with pride that his nephew has finally set himself on the right course to his destiny
If I'm your savior, then you're mine. 