The class is stupefied when Mrs. Hertz gives their reports back: Odd has the best grade in the class and Nicholas has the second best grade, while Jeremie and Laura end up at the bottom with the worst grade. The explanation arrives quickly through Mr. Delmas: the school’s computer system has bugged up badly. The reports are messed up and 6 tonnes of hay have been delivered to the cafeteria. To Odd’s displeasure, the reports are taken back. The heroes wonder if the computer bug was linked to X.A.N.A.. Some of them don’t want to "cry wolf" too early. But the response arrives quickly. Jeremie’s phone sounds, indicating that X.A.N.A. launched an attack. Odd, Aelita, Ulrich, Jeremie and Laura go to the Factory.
They're rather embarrassed, however, when the Superscan doesn't detect any activated tower on Lyoko. They can't really be sure if the computer bug hasn't affected the Superscan and Jeremie's phone as well, so they decide to check the towers before going back to Kadic. The Lyoko Warriors go to Lyoko and scour each sector while Jeremie calls Yumi and William, before starting work at the terminal with Laura. Jeremie gives his friends a small toy of his invention: a portable scan. While exploring the Sectors, this gadget will allow them to locate a tower in a small radius. Unfortunately, the scans detect nothing.
When Yumi and William arrive the three virtualised people finish their exploration of the three Sectors. Laura makes a discover: the Superscan didn’t find the tower because they weren’t looking in the right place; the attack was launched from a Tower in the Cortex! While Yumi and William are virtualised and the other heroes meet up in Sector Five, Jeremie worries. Even if X.A.N.A. has managed to launch a very weak attack from the Cortex, this new strategy by the AI proves that it has become stronger. The heroes board the Skidbladnir and dive into the network.
At the same time, Laura’s phone rings in the lab. Her father is at Kadic Academy and is waiting for her. The young girl is anxious. She finds her father in the principal’s office: he received his daughter’s disastrous mark. The fact that the reports were bugged by the computer error doesn’t calm him at all, and even irritates him: Mr. Gauthier doubts the school’s ability to teach his daughter well. The intervention of Jim, who has just received an order of pink thongs, doesn’t help the situation. In front of the principal’s inability to resolve the bug, Mr. Gauthier is absolute: he’s going to enrol Laura into a different school. He orders his daughter to gather her things for immediate departure.
Far away from there, in the Cortex, the heroes disembark from the Skid. Luck is against them. As soon as the Megapod is virtualised and just before they enter it, a changing of the Sector threatens to throw them and their vehicle into the Digital Sea. They barely escape the danger using teamwork and Odd saves the Megapod just in time.
At Kadic, Laura tries to convince her dad to change his opinion. She is stonewalled by the relentless Mr. Gauthier. She then uses her last resort and takes her father to the Factory. She bursts into the lab and shows him the machine to convince him to let her keep studying at Kadic. Jeremie is helpless. Aelita asks Yumi to devirtualise her urgently with her Tessen Fans. Upon arriving back at the Factory, she proposes to Laura and her dad to “visit” the Supercomputer Room. Mr. Gauthier, a polytechnics engineer, can’t refuse. Aelita takes them to the bottom floor where she locks them in the room and takes the lift back up.
On the virtual world, the heroes get into the Megapod and traverse the Cortex. They’re confronted by two Megatanks. After multiple collisions and fine manoeuvres by Odd Della Robbia, one of the Megatanks falls into the Digital Sea and the other runs into a wall. The heroes than arrive at the activated tower and deactivate it.
After a short debate in the lab, they launch a return to the past to erase Mr. Gauther’s memories. Mrs. Hertz’ class follows, in which the reports are redistributed. And in the correct order this time: Odd is last, Jeremie is the second and Laura has the first place. After the day’s events, the heroes have another debate about Laura in Jeremie’s room. Since the girl is immune to the return to the past, they decide to keep her in the group so they can keep a better eye on her. They then indicate to her that she will only have very limited access to the Supercomputer.
- The original French name for this episode is Chaos à Kadic.
- The first episode that the entire Lyoko team rides in the Skidbladnir at the same time.
- Megatanks are shown on the Cortex for the first time; also, like the Lyoko Warriors, it appears that the Megatanks can be destroyed if they strike a surface going too fast.
- The Cortex is shown to have a Tower.
- Laura's father makes his debut in this episode.
- First time in Season 5 in which a Lyoko Warrior has purposefully devirtualized another member of the team (Yumi on Aelita).
- The MegaPod is revealed to have a weapon, which is used by William in this episode.
- Laura shows the factory to her father, but interestingly, she isn't kicked out of the group.
- It is similar to X.A.N.A. Awakens, Part 2, where Sissi shows Jim and Mr. Delmas the factory, but unlike Laura, Sissi was actually kicked out of the group.
|Code Lyoko Evolution|
|X.A.N.A. 2.0 | Cortex | Spectromania | Mrs. Einstein | Rivalry | Suspicions | Countdown | Virus | How to Fool X.A.N.A. | The Warrior Awakens | Rendezvous | Chaos at Kadic | Friday the 13th | Intrusion | The Codeless | Confusion | An Assured Professional Future | Obstinacy | The Trap | Espionage | False Pretenses | Mutiny | Jeremy's Blues | Temporal Paradox | Massacre | Ultimate Mission|
|Season 1 · Season 2 · Season 3 · Season 4 · Evolution|