Rivalry

William is yet again rejected by the group, but when he asks Yumi for her help on a project she happily agrees, much to Ulrich's disdain. The dislike between the two grows when XANA creates a spectre of William to attack Yumi, and the two almost have a fistfight in the gym.
Soon after deactivating the tower, another one appears. Odd, Aelita and Yumi cannot return to Lyoko as they were there not long ago, so it's up to Ulrich and William to put their differences aside and get Ulrich to the tower to deactivate it. At first the two are showing off and trying to outdo each other, but after William saves Ulrich from falling into the Digital Sea, they call a truce, allowing Ulrich to deactivate the tower. Once back on Earth, William is fully accepted into the group as the sixth Lyoko warrior.