As a Geass user and enemy of the Britannian Empire, Lelouch figures that he will not be able to stay by his sister Nunnally's side. He hopes that his best friend, Suzaku, will be the one to protect her.

However, the conflict between Zero, who has created the "Black Knights" to further rebel against Britannia, and Suzaku, who is ranking up in the Britannian Forces, is about to take a turn for the worse...