Code Geass: Lelouch of the Rebellion officially premiered on the Mainichi Broadcasting System (MBS) television network at 5:25 JST on October 5, 2006, is the first part of the anime series, Code Geass. Its satellite television premiere across Japan on Animax was on November 7, 2006. Upon the airing of the first 23 episodes, the series went on hiatus on March 29, 2007, and completed broadcast of the first series with a contiguous one-hour broadcast of episodes 24 and 25 at 6:25 JST on Saturday, July 28, 2007. The immense popularity of Code Geass: Lelouch of the Rebellion followed with the development of it's sequel, Code Geass: Lelouch of the Rebellion R2, which was first announced on the March 2007 issue of Newtype and later confirmed by Sunrise producer Yoshitaka Kawaguchi on the series' official staff blog on March 9, 2007.
The series is set in an alternative present, where the world is split by three superpowers, Britannia, The Chinese Federation, and the European Union (EU). The story takes place after the Holy Britannian Empire's conquest on Japan in August 10, 2010 a.t.b., by means of Britannia's newest weapon, the "Armored Autonomous Knight", or Knightmare Frame. In turn, Britannia effectively strips Japan and its citizens of all rights and freedoms, and renames the country Area 11 with its citizens referred to as elevens. The series' protagonist Lelouch Lamperouge is an intellectual, exiled Britannian prince, who was sent as a hostage to Japan, along with his sister Nunnally Lamperouge, by his father, Emperor Charles zi Britannia, after his mother, Marianne vi Britannia, was murdered. He then vows to obliterate Britannia. Seven years later, Lelouch meets a girl known as C.C. who, in order to save his life, makes a contract with him. Lelouch then gains a power called Geass (ギアス giasu?), also known as the Power of the King (王の力 Ō no Chikara?), which allows him to absolutely command anyone to do what he wants, bending their will to live, fight, die, and follow orders – though only if he has direct eye contact with his target. With this new power and his natural intelligence, Lelouch sets out to find the person who killed his mother, and to make a better world for his sister, Nunally. He becomes the leader of the resistance movement known as The Black Knights, who wage war on Britannia. As the Black Knights' leader he takes on an alter-ego called Zero, gaining popular support among the Japanese people on his way towards rebellion. Thus getting his power, he then kills one of his older half brothers, Clovis, in an attempt to find out who killed his mother. Various battles between the Black Knights and Britannia, Euphemia li Britannia, one of Lelouch's half sisters and Britannia's third princess announces her intention to form the Special Administrative Zone of Japan in the region under Mount Fujiyama, giving the Japanese people their name and country back. When negotiating with Euphemia, Lelouch agrees to the terms, and reveals his ability to be the source of his massive success, jokingly telling her he could order her "to kill all the Japanese," not realizing his ability had permanently activated several minutes earlier. This forces her to order the Britannian forces to kill all the Japanese people located at the celebration of the formation of the Zone. Lelouch kills Euphemia and uses her massacre as an excuse to attack the Tokyo Settlement. During the rebellion, Nunnally is kidnapped and Lelouch abandons his group to save her. He is opposed by a soldier of Britannia, an Honorary Brittanian, Suzaku Kururugi, Lelouch's childhood friend who is angry at him for killing Euphemia. Suzaku captures Lelouch and takes him to the Emperor who then uses his own Geass to erase Lelouch's memories of being Zero, his mother,and his sister.