The year is 604 ASC, roughly five hundred years after Avatar Aang defeated Forelord Sozan. The world now enjoys a great era of peace, there having been no major conflicts for hundreds of years. There are many small colonies inside the different nations that have immigrated from neighbouring nations.
The lack of any war was slowed the progression of technology with few advancements since the time of Avatar Aang, which may in part be due to the attempt by the Fire Nation to change its’ image in the eyes of the rest of the world, having moved away from military production.
The current Avatar is named Kalley, born into the Earth Kingdom after the death of the previous Avatar, Talia who died in 550 ASC. She is a strong force in the world and does much to ensure that balance between the nations is maintained.