Zuko getting an adorable gleam in his eye, according to his mother, whenever he gets excited. Also, Zuko comes out in panel one with a warm smile, indicating that this feels like a true victory for him.
Every interaction between Kiyi and Zuko.
Kiyi getting along with Aang as well.
Zuko dotes on Kiyi. He very gently tries to get her to be nicer to Ursa by asking her to hold Ursa's hand in case she gets scared on the submarine. There's another scene of him carrying her on his shoulders and putting her to bed.
After spending an entire series as sworn enemies and never properly interacting face-to-face, Mai and Aang finally greeting each other and talking civilly is a welcome sight.
Not only that, Aang ships Zuko with Mai: as soon as he greets her, he excitedly asks if this means they're a couple again. They're... not, and it gets awkward fast, but he just wants Zuko to be happy again.
Ursa sadly reminiscing over the doll she once made for Kiyi's birthday may be a sad scene unto itself, given Kiyi keeps acting cold towards her. But it's still a testament that not only did she regain her memories as Ursa, she also got to keep the memories she made as Noriko.
Iroh apologizing to Ursa for the suffering his family caused her 16 years in the making. Ursa is in fact glad to see him. Following this, she confides all her personal fears about her children. In turn, Iroh not only comforts that Kiyi will eventually warm up to her real face, but gives the much-needed advice that she can face her demons with unclouded eyes.
In its own way, Azula's Hazy-Feel Turn. Even if she's obviously still not right in the head and is as ruthless as ever, she has actually become supportive of Zuko's reign as the Fire Lord and is even willing to destabilize the society that wants to reïnstate their father for him, showing that she is completely done having any loyalty to Ozai.
Also, in the middle of their fight, Zuko actually stops and tells Azula that though it's weird to say this under the current circumstances, he's happier to see that her mental state is better than when he last saw her, with a sincere smile on his face while he says it. As screwed up as they are, these two siblings still love each other.
A mix of this and a tearjerker is Azula is really trying in her own way to make amends with and help Zuko.
Azula has a HUGE and unexpected Pet the Dog moment. When one of her Kemurikage cohorts is about to physically assault Kiyi for mouthing off, Azula stops them, saying admiringly that "the girl's a fighter, it's in her blood". Even though Azula still has issues with her mother, she has gone from seeing Kiyi as Ursa's Replacement Goldfish for her to actually seeing and accepting her as her half-sister in a positive way, even protecting and complimenting her.
Fridge-Heartwarming: That statement "it's in her blood" becomes even more heartwarming when one remembers that unlike Azula, Kiyi isn't descended from Ozai. So who is she talking about? Her mother, Ursa. Or most likely, Avatar Roku, which lends the possibility she knows she's descended from him and proud of it.
For all of the perfectionism and stress she endured that broke her in the series proper. It is somewhat relieving to hear from Azula that she finally feels weightless and free.
For all their fear of Azula striking back at them, Azula barely lays a hit on either Mai or Ty Lee, with most of her fighting back against them being defensive. She might still care for her friends after all.
After seeing Kiyi treat Ursa coldly (due to her new face), the story ends with Kiyi finally having accepted her mother's real face. It could also represent she's come to terms with her mother's royal background.
We learn the origin of the Fire Lord title. Apparently, the first Fire Lord put an end to decades, maybe centuries of strife by uniting rivaling warlords under his banner, and putting an end to the violence and suffering caused by the warlords' fighting. The authors stated that they were looking to establish that, despite the bad rep it got from Azulon and Ozai, the Fire Lord position had its origins in something good.
As it turns out, even the real Kemurikage are not as evil as old Fire Nation stories would have one believe.
Zuko tells Mai outright that he misses being with her, but even though they aren't together, he's actually still pretty happy, political concerns aside. She takes several cheap shots at him, most of which he ignores. When she disparages one of the dates he took her on, he actually pushes right past it, contradicts her, and moves on. He's also mostly respectful to Mai's new boyfriend, although it there are moments of strain, awkwardness, and accidental arrests. It's a huge contrast to the "The Beach" back in season 3, where another guy so much as looking at Mai would set him off. He is by no means a perfect teenage boy, let alone Fire Lord, but he's leaps and bounds ahead of where he started. Because he has good friends like Aang and Suki, Mai and his uncle aren't the only people he thinks care about him anymore. And cheap shots aside, Mai and Zuko actually do manage to work together amicably.
Mai: An ex thought it'd be romantic to share a meal over the burial site of his ancestors.
Zuko: And he was right. It was romantic.
Mai's first reaction to finding out that Kiyi was kidnapped is to give Zuko a big hug. He later takes her hand while assuring her that they'll find Kiyi and Tom-Tom both. When they do find them, there's a panel of both of them holding their little siblings and smiling at each other in relief.
It goes by quickly, but the moment where Iroh comes out of the submarine to meet Zuko. They're both so happy to see each other and hug immediately. They've come a long way...
