The Fire Nation attacked with a large armada of soldiers and tundra tanks, advancing up the steep mountain on which the Northern Air Temple is situated. Aang and the refugees attempted to repel the assault with aerial attacks, utilizing the skill most of the refugees possessed with gliders as well as several types of bombs that the mechanist created. The Fire Nation was eventually defeated when Sokka and the mechanist managed to create a large explosion, using natural gas under the mountain and the engine of their hot air balloon.