S04E04 — Wreck Room

There is a new recreation room at Kadic and William's clone is put in charge of it. Meanwhile, Jeremy has developed a program to get the real William out of Lyoko. However, the program malfunctions and bugs up the tower, allowing X.A.N.A. to take it over while Aelita cannot shut it down. As the William clone lashes out at the group, the real William is on Lyoko to keep the tower under X.A.N.A.'s control. Jeremy manages to repair the tower in time for Aelita to reset it, restoring the clone to working order. With a return trip to the past to erase the unwanted memories of William's behavior at school, the group elects Sissi as the rec room monitor.