Episode Title:
The Secret.
Episode Description:
After being rejected by Yumi, William makes it his mission to find out the secret she's hiding. Soon enough, he manages to follow Ulrich and Odd to the factory and learns about Lyoko and X.A.N.A.. Meanwhile in the Ice Sector, the Scyphozoa possesses Aelita to enter Code: X.A.N.A. in the way tower, but is devirtualized just in time by Yumi. The group thinks William's help is going to be quite useful, when a possessed demolition worker sets several bombs in the factory. They take a vote as to whether or not to include William as part of their group, but Yumi votes no and Jeremy initiates a return to the past.
