-->"I already failed the world once at Ba Sing Se; I won't let myself fail again."

The day of the eclipse has arrived. The invasion party assembles, bringing back some old, familiar faces, and everyone prepares for the coming battle. Using submarines and tanks built by The Mechanist to infiltrate, the invasion is started: Aang heads to the capital to face Fire Lord Ozai, while the invasion force starts battling its way up the city docks and heads for the capital on foot, hoping to secure the defenses by the time the eclipse ends.

!!Tropes

* ActionFilmQuietDramaScene: Preparations for the invasion are interspersed with scenes of Zuko making his own preparations to leave.
* BrickJoke: The snack compartment in the glider.
* TheBusCameBack: Various characters that the kids had met on their travels return to help with the invasion: Teo and The Mechanist, The Boulder and Hippo, the Swampbenders, etc.
* CarFu: Sokka steers a bomb-filled truck into a gate before jumping clear.
* DisorganizedOutlineSpeech: Sokka's attempt at briefing everyone on the invasion plan.
* GondorCallsForAid
* IceCreamKoan:
--> '''Huu:''' Pants are an illusion and so is death.
* ImportantHaircut: Before they leave for the invasion, Aang shaves off the hair that had been hiding his tattoo.
* {{Magitek}}: The submarines and the tanks are propelled by bending and steered mechanically.
* NowOrNeverKiss: Aang, realizing he might not return, kisses Katara just before he leaves, effectively revealing his feelings to her.
* PostKissCatatonia: The above causes this for Katara.
* RousingSpeech: After Sokka fails miserably at this, his father takes over and shows everyone how it's done.
* ShutUpKiss: Aang's NowOrNeverKiss with Katara is also one of these.
* ToiletHumor: Subverted. Huu says he's been gone to answer the call of nature... by which he means that he needed to find a lot of seaweed.
* [[YourPrincessIsInAnotherCastle Your Enemy Is In Another Fortress]]: Aang charges into the throne room ready for his UltimateShowdownOfUltimateDestiny against the BigBad EvilOverlord... and he's not there.