UnaVaatu attacks Republic City, and the United Forces led by General Iroh are no match for the Dark Avatar. His attacks cause a large number of spirit vines to envelop a large portion of the city, and give Varrick the distraction he needs to break out of jail with Zhu Li.
Tenzin finds the despondent Korra, now permanently severed from the past Avatars. He takes her to Vaatu's prison, the Tree of Time, where he informs her that she is not defined by Raava any more than Wan was. He encourages Korra to connect with her spiritual energy to fight UnaVaatu. After reflecting on Raava's claim that she can never be fully destroyed, only reduced to a small light in Vaatu's darkness, Korra succeeds in doing so, and her spirit leaves her body and grows to immense proportions and departs for Republic City.
Korra engages Unalaq in a colossal battle in Republic City's bay. Korra attempts to extract Raava from UnaVaatu, but is unable to do so, and the Dark Avatar overwhelms her. As Unalaq prepares to destroy Korra's spirit, Jinora appears from the sky and somehow helps Korra find Raava and extract her from UnaVaatu. Korra then uses Unalaq's spiritual pacification technique to purify UnaVaatu, destroying the Dark Avatar Spirit, defeating Vaatu for another 10,000 years, and killing Unalaq.
During the battle, Tenzin, Bumi, Kya, Mako, Bolin, Desna, and Eska have defended Korra's body from Dark Spirits, and Korra returns victorious just as they are overwhelmed. As Harmonic Convergence ends, Korra merges with Raava, essentially restarting the Avatar Cycle, meaning that Korra nor any future Avatar may consult or see any previous Avatars ever again. Korra decides to leave the spirit portals open, believing Wan made a mistake all those years ago.
Eska and Bolin break up, and the twins return to the North Pole with their troops. Mako and Korra also break up for good. Jinora returns to life, and Korra announces the beginning of a new spiritual age for humans and spirits.
Was released a week early at midnight, the same day as the previous two episodes were aired. Can be watched on Nick's website here.
- Attack of the 50-Foot Whatever: Korra is able to separate her spirit from her body and turn giant like Vaatu/Unalaq.
- Beam-O-War: Korra and Vaatu have one. Korra wins easily, but that's only the opening volley.
- Big Damn Heroes: Desna and Eska save Bolin and help protect Korra's body, while Jinora's spirit saves Korra from being destroyed by Vaatu and Unalaq and helps her locate Raava within him.
- Big "NO!": Unavaatu has one after Raava is reawakened.
- Bittersweet Ending: Korra restores Raava, defeats Vaatu and Unalaq, regains her Avatar powers and now spirits can freely enter the mortal realm. Unfortunately, she loses her connection with all of her past lives and truly breaks up with Mako. Of course, Varrick is still out there and at large.
- Korra accesses the cosmic energy in the same way Aang tried to in the finale of Book 2 in his own show.
- Also, Korra remembers how Raava told Wan that if she was to be destroyed by Vaatu, she would grow again within her counterpart and reemerge, and manages to use this to restore the light spirit and defeat Vaatu and Unalaq.
- Combat Tentacles: The Dark Avatar
- Continuity Nod: Bolin's "Eska! I love you!" is the exact same thing he said to Mako when the latter saved him from Amon in the first season.
- 11th-Hour Superpower: A twofer. While the previous episodes did establish the fact Jinora has an unusual affinity with the Spirit World, the way she uses her "spirit powers" to help Korra to defeat Vaatu still comes almost completely out of the blue. Also, Korra using soulbending to take on UnaVaatu is established to be due to being in the Tree of Time during Harmonic Convergence, giving her spiritual power a major boost. Which actually explains Jinora's power somewhat...
- HeelFace Turn: Eska and Desna finally turn against their father when the full magnitude of his Demonic Possession and resultant Omnicidal Maniac tendencies become apparent.
- Hoist by His Own Petard: Vaatu and Unalaq is defeated by Unalaq's own spirit-bending technique.
- Hold the Line: While Korra's spirit battles Unalaq at Republic City, everyone else fights tooth and nail to keep the encroaching horde of dark spirits away from her body at the Tree of Time.
- Ironic Echo: "I support whatever decision you make". Originally said by Mako early in the season, as a fairly insincere way to support Korra without angering her. Repeated here by Tenzin, as a genuine sign that he trusts her to act wisely.
- Monumental Damage: Vaatu rips Aang's statue off its pedestal. It's amazingly durable, though, coming off completely intact. They just need to put it back.
- Nothing Is the Same Anymore: Mako and Korra stay broken up, and the spirit portals remain open permanently, allowing humans to visit the spirit world and spirits to visit the material realm. Korra's connection to her past lives is also permanently broken.
- Oh, Crap!: Unalaq has one after Raava is reawakened.
- One-Winged Angel: After tapping into the cosmic energy, Korra is able to separate her spirit from her body and become as big as Vaatu/Unalaq.
- Ship Sinking:
- Sorta. Mako and Korra break up for real, and apparently permanently, but restate their love for one another as well.
- Also, Bolin and Eska decide to remain apart despite their new-found (or renewed, in Eska's case) affection for each other.
- Single Tear: Korra does this after breaking up with Mako.
- Villain Exit Stage Right: Varrick manages to escape in the midst of the chaos caused by the attack on Republic City.Varrick: "Zhu Li! Commence Operation Winged Freedom! Do the thing!"
- When Trees Attack: Vaatu and Unalaq covers Republic City in vines.