Lelouch arranges to obtain the same kind of immortality C.C. has without her, nor anyone else knowing. He preforms the ritual himself in the smoking ruins of the now-dead cult's headquarters.
Later, Lelouch successfully assaults Britannia, lays waste to the royal palace and kills his father. He casually remarks to himself, "now there is only one enemy left..."
He meets C.C. soon after, and she betrays him by robbing him of his Geass and shooting him through the heart.
A group of Black Knights comes upon the two of them and they angrily question C.C. as to what happened to their leader. C.C. claims that Lelouch died on his way to kill the Emperor, and that she did it in his stead. She demands to be the new leader of the Black Knights and the new world.
Halfway through the conversation, the Black Knights abruptly stop talking. They stare, shocked, at spot behind C.C. Two footsteps can be heard as Lelouch rises from his place on the floor, and as C.C. turns around he laughs the most cruel, mirth-filled, evil laugh he has ever laughed as the cult symbol glows on his forehead and he regains his Geass.