In the world of Avatar the Last airbender, there are two people who can lay claim to being the best Earthbender in the world.
Toph Bei Fong, the champion of the Earth Rumble
Bumi, the King of Omashu
This decide to go head to head to determine who is the best there is.
Both are in charactef, doing this out of a sense of competitive spirit.
The fight takes place in the city of Ba Sing Se