Some time later Katara has developed into Master Pakku’s star pupil, earning her his highest praises. Sokka and Yue spend more time together including a ride on Appa, during which Sokka notices a storm of “soot”, a tell-tale sign of an impending Fire Navy raid. As the tribe prepares for battle, the chief asks for volunteers for a dangerous mission, to which Sokka immediately agrees. As Zhao’s armada closes in, Iroh meets with Zuko in disguise as a Fire Nation guard, as he tells Iroh that he’s working on a plan of his own. As the Northern tribe takes up battle station, the raid begins. Aang and Appa work to help disable the lead ship, but are overwhelmed at the size of the fleet that follows. In preparation for the chief’s secret mission of infiltrating the Fire Navy, Sokka clashes with a Northern soldier before realizing he is Yue’s future husband. As nightfall nears, Iroh warns Zhao to halt the attack as the waterbenders will draw power from the nearly-full moon. Zhao cryptically notes he is working on a solution, but agrees with Iroh for the interim. Iroh then meets up with Zuko, who plans to kayak from Zhao’s ship and infiltrate the North Pole to capture Aang. He nearly drowns after choosing to free swim under the glacier to find a way in, but is able to infiltrate the city. Meanwhile, Aang and Katara are brought to a spiritual oasis at the top of the city by Yue, with Aang hoping to find the Moon and Ocean spirits for help. Aang begins to meditate in front of a koi pond with two fish circling each other, and when he realizes they resemble Yin and Yang he crosses into the spirit world. Zuko arrives shortly after and battles with Katara until sunrise, when he overpowers her and escapes with Aang’s body as the Fire Nation resumes the attack.