Season finales need to pay off everything the season has built. Avatar: The Last Airbender season 2 episode 7 "Something Broken" does this, and then goes a bit further.
So far this season, Aang and the gang arrived in Ba Sing Se to warn the Earth King about Sozin's Comet, planned to use the Day of Black Sun to strike before it arrives, and watched it all fall apart piece by piece. Long Feng turned out to be running the city from the shadows. The Earth King meeting fumbled when Aang entered the Avatar State at exactly the wrong moment. The team fractured in a fight that left real damage. Katara was arrested. Sokka was captured. Toph was drugged by her own mother. And Appa, whose disappearance has been weighing on Aang since episode 5, is somewhere underground with the Fire Nation closing in above. Azula, meanwhile, has been quietly absorbing every piece of power the city had to offer and by the time episode 6 ended she had most of it.
Now the finale is the episode where all of it comes together pretty well. It is also the episode where Toph invents metalbending and where we (finally) get Katara and Zuko scenes. Quite like the entire season, it is still surprisingly intimate in its best moments. The big action sequences are here, but what it's about, as the title suggests, is what happens when things break between people and within people.

Episode 7 recap
The episode opens in the past with young Aang choosing Appa from a pen of sky bison and the two of them immediately bonding. It is brief and warm and sets up everything that follows, because finding Appa is what drives Aang through the entire episode.
Present day, Toph confronts Lady Beifong about the family's Fire Nation weapons contracts. Her mother insists she believed they were for farming equipment and promises to cancel them, adding that she always hoped Toph would eventually take over the business. Toph admits she got into a fight with her friends and isn't ready to go home yet, but promises to talk to her mother again once she's made things right with Team Avatar. Lady Beifong agrees to wait, and the two share tea during which Toph starts to feel strange and disoriented, and it's revealed her mother has drugged her tea.
The group is still scattered. Sokka and Sai are imprisoned underground at Lake Laogai. Katara has been captured by the Dai Li and is in a cell, and discovers, to her horror, that Zuko is in the adjacent one. He helped her when she was attacked and got arrested for it. Neither of them particularly wants to be there with the other.
Above ground, Azula has completed her takeover. Long Feng's arrest of General Sung and the military leadership has played directly into her hands. She absorbs the Dai Li with barely any negotiation required. Long Feng, in his cell, finally understands what she has done and has no move left. Ba Sing Se's Fire Nation occupation begins.
Aang, alone with Momo and helped by refugees from Omashu, pieces together where his friends are being held. He finds Iroh, who has also come to rescue Zuko, and the two of them form an unlikely alliance, entering the prison through a hidden door that requires bending all four elements to open.
In their cell, Katara and Zuko's conversation is the episode's most emotional beat. She confronts him with the full account of what the Fire Nation has taken. Waterbenders killed or captured, her mother gone, her own guilt at having survived by hiding. Zuko doesn't deflect. He tells her his father burned him. That part of him believed he deserved it, and that part of him let it happen. They reach each other through their losses. Katara offers to try healing his scar with water from the Spirit Oasis that she has been carrying since the Northern Water Tribe. He says he doesn't deserve it. She asks if she can try.
Sokka and Sai escape their cell through applied chemistry. The prison walls contain crystals with different properties to stone, and Sai works out a way to dissolve them. Toph, meanwhile, is being taken home in a carriage. She wakes up to what has happened and discovers she can feel the metal walls of the carriage through her earthsense. The crystals in the metal, the impurities left from the ore, still carry the memory of the earth they came from. She bends them. The carriage comes apart. Toph Beifong invents metalbending on the way home and turns back.
The group reunites underground. Aang finds Appa. Long Feng, cornered, tries one more play by warning Aang that Azula has taken the city and suggesting they run together. But Aang refuses. The group then reunites in stages. Aang finds Sokka, then Katara and Zuko, with tensions flaring before Zuko's help is validated. Aang and Katara share a tender moment reaffirming their friendship, regardless of duty or expectations.
The final confrontation with Azula brings everyone into motion. Zuko and Azula fight, and she offers him a version of coming home, they could share this victory, she says, invoking their mother's instruction that they stay together. They reconcile.
Aang, facing Azula, enters the Avatar State. She fires lightning into it. He goes down. Katara pulls him out. Iroh holds off the Dai Li long enough for the group to get Aang onto Appa and escape. As they rise above Ba Sing Se, the Fire Nation flag is going up over the palace. Katara works over Aang with the Spirit Oasis water, pouring everything she has into it though it seemingly doesn't work.

Episode 7 review
As finales go this one is doing a lot, and it mostly pulls it off. What helps is that it never loses sight of what the season has actually been about and pays those things off before it worries about the action.
The Katara and Zuko cell scene is the obvious highlight and it deserves to be. Two characters who have been on opposite sides of every confrontation for two seasons and they finally get to open up.
Toph inventing metalbending is such a great TV moment. It happens alone, in a cage, out of pure stubbornness. The Miss me, Snoozles? line that follows is so her.
The rescue sequences are busy and occasionally hard to follow, but the emotional logic is clear throughout.
Zuko and Azula reconciling over their mother is the episode's most surprising beat and the one that will probably be talked about most going into a potential third season. I totally did not see that coming and would say I was pretty bummed about it, given how the season had seemingly been building toward a Zuko redemption arc. However, it doesn't feel cheap because the show has done the work on both characters. Azula is genuinely feeling something in that moment. Whether she was actually being honest about it going forward is a question season 3 will have to answer.
Aang going down in the Avatar State in the finale was foreshadowed since the Spirit Library sequence. Yangchen told him in episode 5 what it would cost if he fell in the Avatar State, and when he enters it out of desperation, he pays the price. It's a gutsy way to end a season but it works.
