On August 10, 2010, a.t.b. (the Imperial calendar, roughly 2060 A.D.), the Holy Empire of Britannia overpowered Japanese forces and conquered the country with their new robotic weapons, the Knightmare Frames, in less than a month. In the aftermath of Britannia's invasion, Japan lost its freedom, its rights, and even its name, becoming Area 11 of the Britannian Empire. The Japanese people, renamed as "Elevens", are forced to survive in poor neighbourhoods, while Britannians live in first-class settlements. Rebel elements persist, however, as pockets of Japanese organizations struggle against the Empire for the independence of Japan.
After his father, the Emperor of Britannia, failed to prevent the assassination of his mother, an attack which also left his sister blind and crippled, the young prince Lelouch vowed to destroy Britannia. Seven years later, he accidentally becomes mixed up with "terrorists" in Area 11 and encounters a mysterious girl named C.C., who gives him the power of Geass. With it, he finally has the power that he needs to defeat Britannia and fulfil his two wishes: to seek revenge for his mother and to construct a world in which his beloved sister Nunnally can live happily.

8月10日， 2010年， a.t.b. （帝国日历，大约公元2060 ） ，罗马帝国的不列颠压倒日本军队和征服的国家，其新的机器人武器， Knightmare框架，在不到一个月的时间。之后不列颠入侵，日本失去了自由，其权利，甚至它的名字，成为区11 Britannian帝国。日本人民，更名为“ Elevens ” ，被迫生活在贫民区，而Britannians生活在一流的定居点。叛乱分子仍然存在，但是，由于日本的口袋里组织的斗争帝国独立的日本。

经过他的父亲，皇帝的不列颠，未能阻止暗杀他的母亲，攻击也离开了他的妹妹失明和瘫痪，年轻的王子路许誓言要摧毁不列颠。七年后，他意外地成为混合与“恐怖分子”地区11日和遇到一个神秘的女孩命名为连铸，谁给他的权力Geass 。有了它，他终于有能力，他需要打败不列颠，并履行他的两个愿望：寻求报复他的母亲和建造的世界中，他心爱的妹妹Nunnally可以快乐地生活。

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