The Geass sigils in Nunally's eyes grew larger and larger until each eye was shining pure white. She did not blink, and she wound her fingers together in front of her as she stood still, allowing her power to go about its assigned task.
Lelouch would never forget that day, that moment, when he had seen Nunally's hand take up the graceful fingers it was offered, and known in a shocked instant what his sister and his supposed ally had done.
("You who have so long been blind, Nunally," the voice still echoed in his head, "now see!! SEE EVERYTHING!!")
Geass had granted Nunally the power of Unlimited Sight. It had permanently overcome her psychological blindness, but it granted her a far more expanded power to observe than any mere eyes could deliver. With her Geass, Nunally could observe things that were happening far away- all the way on the other side of the world, even. Her mind's eye could not be repelled by walls or fortresses; she could See things that happened in secret and when no one else was watching for them.
But that was not even the end of her power. Nunally could See, not only through space, but through time. She could perceive the past- and she could predict the future. All of reality was open to her observation.
There were only two limits. Firstly, the power could only be employed once a day. Secondly, Nunally could not initiate it on her own; she required that someone ask her to look for something before she would be able to search for it.
Nunally's eyebrows rose; her face relaxed and she began to move her muscles again. Her eyes, however, remained wide open, and they were blank circles of glowing white.