The world of Wings of Geass is mainly divided amongst three international superpowers: the Holy Empire of Britannia, the Chinese Imperial Federation, and the European Union. Australia has remained independent, and is not a major player in international politics, instead becoming a neutral state akin to real-world Switzerland. The Middle Eastern Federation is not a supernation, however, it is believed to have warm relationships with the E.U. and also being fairly democratic.
On August 10, 2010 a.t.b., the Holy Empire of Britannia overpowered Japanese forces and conquered the country with their newly-developed robotic weapons, the Knightmare Frames, in less than a month. Japan lost its freedom, its rights, and even its name, becoming "Area 11" and its people "Elevens". The Elevens are forced to survive in ghettos while Britannians live in first-class settlements. Rebel elements persist, however, as pockets of Japanese resistance struggle against the Empire for the independence of Japan, partly due to Japan surrendering before all of its human resources would have been depleted in the struggle against the Britannian invasion. The Japanese resistance movement is supposedly unrivaled amongst such movements.
After his father, Emperor Charles zi Britannia, did nothing to pursue the terrorists who murdered his mother and crippled his sister, Lelouch vi Britannia vowed to destroy Britannia after being banished from his home. Seven years later in Area 11, he encounters a mysterious organization called the Order of Zarathustra. This ancient religious society believes Lelouch to be the "seed of chaos" that will destroy the world, and create a new one in its place. With the Order siding with Lelouch, he finally has the power he needs to defeat Britannia and fulfill his two wishes: to seek revenge for his mother and to create a world where his beloved sister can live happily.