In a war torn world where every nation is fighting and deceiving each other for absolute dominance, one of the three superpower nations known as The Holy Empire of Britannia rule most countries including Japan. After taking over Japan they further establish dominance by semi-enslaving the Japanese people and even stripping them of their culture and rights to call themselves Japanese, making it illegal and somewhat demoralizing. Japan is therefore known as Area 11 and the Japanese people as Elevens.
The only way "out" for the Eleven's was to apply for a Britannian passport and be known as "Honorary Brittanians" in which they would still be victims of racism and prejudice but given a false peace of mind and allowed an education and overall better treatment than the Elevens.
Code Geass follows the life of Lelouch Lamperouge (real name: Lelouch Vi Brittania), a boy who was abandoned and shipped off to Japan along with his blind and crippled sister Nunnally, by their Parents Charles Zi Britannia, the king of Britannia and Marianne Vi Britannia who has passed away since Lelouch was a young boy.
Now in college, the only thing Lelouch really wanted to do was to protect his sister and to bring down the Holy Empire Of Britannia. His wish seemed to come through when one day he met CC (said as Cee-Two), who gave him the power known as Geass (Each Geass is unique- some stronger than others). Lelouch's Geass allowed him to give an order someone must absolutely follow once he made eye contact with them but he could only use it once on that person.