Episode 12: "Enter the Void"
After taking over the Northern Air Temple and capturing all of the airbenders, Zaheer has demanded that Korra turn herself over, but he has yet to share what he intends to do with her. While sisters Lin and Suyin debate how to outplay Zaheer and the Red Lotus, Korra decides to submit to Zaheer's wishes, concerned that there is no other way to save the airbenders. Team Avatar splits into two groups: Mako, Bolin, and Asami head to the Northern Air Temple to retrieve the airbenders while Korra gives herself up to Zaheer, while her father Tonraq, Lin, Suyin, and Suyin's metalbending forces back her up.
Before Korra arrives, Zaheer shares a tender moment with P'Li (who is crazy taller than him and, as always, looks amazing). We learn that Zaheer rescued the combustionbender from a warlord, and the couple exchanges loving words and a kiss. At the same time, Korra hugs her friends before she parts and her father shares how proud of her he is in a fairly ominous goodbye.
Throughout the season, Zaheer has referenced a particular airbendeder named Guru Laghima, whose locket he stole from Air Temple Island. The location Zaheer chooses to meet with Korra is Laghima's Peak, named after the ancient airbender, and it is here that everything blows up.
Korra allows herself to be put in chains by P'Li after Mako informs her over the radio that he, Bolin, and Asami are with the airbenders and a badly beaten Tenzin. Once Korra is restrained, Mako notices that the "airbenders" behind Tenzin are decoys created by armless waterbender Ming-Hua. Three fights begin at once: Korra, in chains, and Tonraq focus on Zaheer while the metalbenders, led by Lin and Suyin, deal with P'Li, and back at the nearby Northern Air Temple, Ming-Hua and lavabender Ghazan attempt to take out Asami, Mako, Bolin, and Tenzin.
The fight is brief in the Northern Air Temple. After the two sides exchange a few blows, Ghazan turns almost the entire room to lava, trapping Korra's friends. After using Bolin's earthbending to push through walls and taking secret paths through the temple, the group soon realizes they cannot escape the oncoming lava. Jumping in front of everyone, Bolin goes for broke and stops the lava himself. Maybe he can't bend metal, but Bolin is one of the rare lavabenders! Kai, the one airbender to escape the Red Lotus, retrieves the team and they leave to rejoin the rest of the group, but the Northern Air Temple is completely destroyed.
On Laghima's Peak, Korra proves capable of holding her own against Zaheer even when restrained, but it is still not quite enough. Tonraq pops in and cuts loose Zaheer's airship and does his best to assist Korra in the fight, but is soon blasted off the cliff by Zaheer. Korra calls out to him and watches her father presumably fall to his death.
P'Li proves too powerful for all the metalbenders, her ability to cause explosions almost instantaneously is more than anyone can handle. Eventually, Suyin and Lin are pinned down and Lin jumps out to distract P'Li so her sister can escape. As P'Li powers up a blast to kill Lin, Suyin metalbends her own armor around P'Li's head. There is no blast, no sound of explosion. Zaheer turns back to see the spot where his lover once stood, only a pillar of smoke remaining. The antagonists this season have been fairly likable most of the time, and after the scene between P'Li and Zaheer earlier, P'Li's death hits a lot harder than I would have expected. Zaheer quickly knocks out Korra and steps to the edge of the cliff, but with his airship floating away, and there is no escape.
Lin and Suyin corner Zaheer, demanding he release the Avatar, but instead he repeats a quote from Guru Laghima heard earlier in the episode, "Let go your earthly tether. Enter the void. Empty and become wind." Zaheer falls from the peak and takes flight. No flying bison, no airbending staff. Zaheer can straight up fly, Superman-style. Later, Ghazan and Ming-Hua walk in on Zaheer floating as he meditates, and they inquire about his new ability. Zaheer replies that he was not sure he could, that only Laghima had unlocked be ability before, and that it only became possible once he freed himself from worldly desires. It is no coincidence that Ming-Hua then ask what happened to P'Li.
In Avatar: The Last Airbender, Aang was never able to access his seventh chakra, because to do so he would have to sever himself from all earthly desire, the last of which being his love for Katara. Now, in the wake of P'Li's death, Zaheer has done what Aang could never achieve and has become untethered to this world. He's lost his love, but as we see in the fight of the next episode, it would appear that he has become the most powerful airbender we've seen yet.
Back at the base of Laghima Peak, everyone reunites. Tonraq thanks metalbender Kuvira for rescuing him. While she has relatively few lines in this episode, Kuvira, voiced by the daughter of the late Robin Williams, Zelda, received a special focus in those moments, with the camera zooming in on her face and meaningful music playing. The character had appeared for a few moments in a previous episode, and it would appear that the show is setting up for her to be a significant character in Book Four.
Kai reveals to the group that he knows where Zaheer has taken Korra, and Tenzin's sky bison Oogi returns. The group departs to save Korra, who awakens in chains in a cave. She screams at Zaheer, accusing him of killing her father, while Zaheer reveals that he also lost someone he loved, but at least Korra's pain will soon be over.