The Black Knights finally defeated their long time nemesis, the Holy Britannian Empire over ten years ago. Zero had obtained this victory by assassinating Emperor Lelouch vi Britannia, a man who was hell bent on taking over the world beneath an iron fist. Now, the world is finally at peace. The United Federation of Nations is the lone 'superpower' left in the world, with the United States of Japan leading the way in a new wave of democracy. Even Britannian, which has since been known as the United States of Britannia, has changed its ways and adopted a more democratic way of life as well. It appeared that Zero's aspirations for a world where all of its citizens lived in peace and harmony was finally unfolding.
However, in the shadows stood the Britannian Restoration League, a group of bitter and vengeful individuals formed by the former dukes, duchess, and other powerful political figures in the Britannia of old. They weren't about to allow Japan its sought out peace. They had every intention to restore the Holy Britannian Empire as their rightful superpower in the world and reclaim their dominant place in society. So long as the Black Knights existed, so would the BL. They will not stop until the war from ten years ago is nothing more than a bitter memory.
Now the two sides are deadlock amidst the start of another war, with the world powerless to do anything but watch on. How will this story of bitter rivals play out? Who will be victorious?