Fight to the Finish.With the Skid gone and X.A.N.A.'s Replikas at unmanageable numbers, Jeremy continues work on his multi-agent system. Meanwhile, Aelita has nightmares about her father being killed by X.A.N.A.. As Jeremy works, he is contacted by Franz Hopper, who arranges a meeting on Lyoko. William wants to help, but all except Aelita are a little wary of trusting him again. William is left in the lab with Jeremy. After meeting up, Franz transmits the data necessary to finish Jeremy's multi-agent system. However, X.A.N.A. is not willing to give up without a fight, activating a tower to possess William once again while sending the Kolossus to deal with Franz. Yumi willingly devirtualizes herself and fights William while the others protect Franz. Once Franz is finished transmitting the data, Aelita and Odd head to Carthage to launch the program. Ulrich, meanwhile, manages to defeat the Kolossus, but its corpse falls on Ulrich, devirtualizing him instantly. However, a problem arises: the energy requirements are too great. Aelita's nightmare is realized when Franz makes the ultimate sacrifice, himself, to power the program, and in doing so X.A.N.A. is wiped out completely. Though a great victory for them, the loss of Franz Hopper leaves them with little reason to celebrate.