Season 3 Finale/Season 4 AU. What if William was never possessed by Xana? What if the other Lyoko Warriors were? Well, that's exactly what happens. In the aftermath of Lyoko's destruction, William Dunbar is the last Lyoko Warrior remaining and must fight Xana with the help of Jeremie. Why does he fight when the odds are against him? One reason; Yumi Ishimaya. (Full summary inside.)