Like I said,
Avatar: The Last Airbender - The Burning Earth follows the events of the second book in Aang's adventure. He has already mastered Air and Waterbending and now he must find an Earthbender to teach him his next element. After leaving the Northern Water Tribe, Aang will travel into the Earth Kingdom only to find that not only is Omashu controlled by the Fire Nation and his old friend King Bumi has surrendered, but he will eventually find the Earth Kingdom's capital, Ba Sing Se, under siege.
During the Aang, Sokka and Katara's travels to the heart of the Earth Kingdom, they will meet a blind Earthbender named Toph who, because of her inability to see, uses the ground and vibrations to know what is going on around her. The young girl joins their group and starts to teach Aang what he needs to know in order to Earthbend.
Avatar: The Last Airbender - The Burning Earth will have you and one other character running around various cities performing random fetch quests in order to progress the story. While navigating the locations, you will run into enemies. When this happens, the screen blacks out and you will have to fight the enemies that have appeared. After all the foes are defeated and you've collected whatever they've dropped, you can resume trekking through whatever location you were in. So, let's say you were in the occupied Omashu and you see a Firebender approaching you. When he comes in contact with either you or your companion, the screen will go black, and you will find yourself surrounded by two or three enemies. At first I was annoyed at this. I wasn't sure I liked the fact that I had to stop my running around just to do some fighting, but eventually I came to accept it, and besides a few times when it got repetitive, I didn't have any problems with it.
As you fight, your characters level up. Eventually they will learn more bending (or in Sokka's case, weapon) skills that take increasingly more Bending Points. For instance, Aang's Air Blast takes only one point, while his Tornado takes all four. These points are displayed around the portrait of the character you are controlling and you can watch each point slowly rebuild over time.
There are even a few mini-games sprinkled here and there throughout The Burning Earth. The first one you encounter and probably one of my favorites is the one where Katara has to help the wounded in an Earth Kingdom outpost. You do this by tapping all of the bandages on the patient. As you tap them, they fly off and when all the bandages are gone, the patient leaves and you get the next one. At first this starts off with large, easy to hit bandages, but eventually you will have to take out layers of bandages, small bandages scattered all over the body or even the occasional fully bandaged soldier. They offer nice distractions to the game and really keep it from getting too repetitive.