Code Lyoko - Season 3 Episode 12
Double Trouble

With Xanas attacks becoming more and more difficult to handle, the group contemplates adding another member to the team to make things easier. William is still the prime candidate, but Yumi still doesnt trust him. While Jeremie works on a way to get to Sector 5 directly, Xana makes a clone of him and has it take Jeremies place. Meanwhile, Yumi has missed one too many classes, and will be expelled if she misses another. Odd and Yumi end up bugged by Jeremies clone, preventing them from rescuing Aelita from the Scyphozoa. The Scyphozoa possesses Aelita, having her enter Code:Xana into the way tower, wiping out The Mountain Sector, cutting off access to Sector 5. However, Jeremie completes his program to send the group to Sector 5 directly.