Charles has taken V.V.'s immortality.
C.C.'s ultimate goal is for Lelouch to take hers. Or it was, anyway. She arrives to confront Charles and sends Lelouch into her own memories.
But Lelouch will not be removed. After learning C.C.'s history, he returns and destroys the Sword.
Lelouch rescues her from the collapsing subspace and they escape through the mystic door.
But C.C. has lost her entire memory, regressing to the mind of a medieval slave.