The episode begins with a pan-shot of the Desert Sector, including a strange noise and activated tower. In Odd and Ulrich's room, Kiwi in laying on Odd's bed. The lamp attached to one of the tables starts to shake and the light bulb comes out, followed by X.A.N.A. being careful not to break the bulb; it sets in on the table. Kiwi starts to growl and bark at the ghost. The view changes to the hallway outside the room and you hear Kiwi bark a couple more times.
The bell rings and you see the group standing around, waiting for Yumi, who comes to them asking, "Hi, so how did the Italian test go?", to which Jeremie replies saying that he doesn't understand Italian, but Odd, being Italian, does, saying, "You're really lame in Italian, Jeremie, old buddy," in Italian. Sissi walks by them with Milly and Tamiya following her asking questions, which annoys her.
Later that evening, in the cafeteria, Odd and Jeremie are waiting in line, and Aelita and Ulrich are already sitting down at a table. Odd and Jeremie are arguing in the line about Kiwi, with Jeremie saying how unintelligent Kiwi is, and Odd sticking up for him.
Meanwhile, Milly and Tamiya are walking down a hallway to go to the bathroom and take a shower. They find Kiwi sitting in the hallway and they become worried that Odd will get in trouble with Jim. Tamiya then offers to take Kiwi back to Odd's room while Milly goes into the shower room. Tamiya then walks over to Kiwi, the picture shows the eye of X.A.N.A., and Kiwi starts growling and barking at her. While reaching down, Kiwi bites her wrist. She gets dizzy and then becomes the first zombie of the episode. She then attacks Milly in the shower, but Milly overpowers her and gets away.
Back in the cafeteria, the group is still eating their food. Odd says, "So are you going to eat you chocolate pudding?" to which Aelita responds, "Isn't that your fourth one?" Milly then comes running in screaming that Tamiya attacked her, to which Rosa Petitjean, the cook, tries to comfort her, while Jeremie uses the Superscan on his laptop to see if there is an activated tower on Lyoko. When Jeremie finds that a tower is activated, they decide to go to the Factory, and Ulrich calls Yumi and tells her to meet them there. Yumi is shown having dinner at her house with her family when Ulrich calls. Hiroki then bothers Yumi, giving Yumi an excuse to leave the table, saying that she's going to bed.
Back at the cafeteria, Rosa starts to think Milly is serious and tells Sissi to go get her father, to which Ulrich says they'll go with her, which brings a smile to Sissi's face. When they leave the cafeteria, they immediately see Jim. Sissi tells him that there's a problem with Milly and they find out that he too is a zombie. Sissi takes off running, away from Jim and the others. Ulrich tries to get Sissi to come back, but when it doesn't work he goes after her, telling the others to meet up at the Factory. Aelita then points out the zombies walking towards them to eat their flesh due to zombies being hungry all the time. They then turn back into the cafeteria. Odd tells Rosa that they're surrounded by zombies and she faints. Yumi is then shown sneaking out of her house, and Sissi running down a path to which she then finds more zombies. Ulrich finally catches up with her and fights off the zombies.
In the cafeteria, it is being surrounded by the zombies and Milly says, "See, I wasn't dreaming!" While the zombies walk away from the door, William is talking to the cops on his phone, but they don't believe him about the zombies. When Odd, Aelita, and Jeremie try to leave the cafeteria to get to the factory, William doesn't let them. While all this is happening, Yumi manages to make it to the factory. Ulrich is then shown to be hiding in some bushes with Sissi. They then decide to go back to the cafeteria thinking it’s a safe spot. Back in the cafeteria, Odd and the others tell William about the Supercomputer, Lyoko, and X.A.N.A., but he doesn't believe them. When he still doesn't let them go, they go to plan B, which is Odd distracting William, while Jeremie and Aelita try to get out. When William is completely distracted, they try to get out, but it doesn't work for them as Herb sees them and tells William, who then pushes Jeremie down saying, "Sorry, but it's for your own good. You'll thank me when you get out of this safe and sound."
Back at the Factory, Yumi makes it down to the lab, to which she finds deserted. The picture then changes back to the school, but to the outside gates. A couple of police officers are there. They get the attention of a worker, they ask him if he's seen anything out of the usual, to which he says he hasn't and the police leave. Ulrich is then seen running with Sissi to the cafeteria still, he calls Jeremie asking them if he's made it to the Factory yet. Back at the gates, the gatekeeper sees Jim and the other zombies. Ulrich and Sissi are then shown in the bushes again, but they leave again when they see all the zombies. He calls Yumi, who asks where they all are. Ulrich tells her that there's a living dead convention at the school and that he's trying to think of a way to get Aelita and the others to the Factory, but it'll be hard. Back in the cafeteria, Kiwi somehow gets in without anyone letting him. Odd then sees him and goes to pick him up, but while he's picking him up, Milly tells them that that is the dog that they saw before Tamiya became a zombie. Kiwi bites Odd on his hand and Odd sees the eye of X.A.N.A. in Kiwi's eyes. Odd then turns into a zombie and they force him onto the ground and tie him up. Jeremie then tells William again about X.A.N.A., saying that Kiwi is possessed. Ulrich then goes out to distract them so that Sissi can get in the cafeteria. While all the zombies go after Ulrich, Sissi goes to the cafeteria telling them to let her in, but Herb says its not her, and to prove it. Sissi then says, "Um, I uh, I have a subscription to Pretty Girl, and I still sleep with my stuff moose.", to which doesn't work and Herb still won't let her in. She then insults everyone in the cafeteria when the zombies come back and Nicholas says, "Okay, that's Sissi alright." When Herb opens the door for Sissi, Jim pushes in and Nicholas tries to throw a chair at him and then William tries to fight him, but it doesn't work for him and he's is thrown outside to the other zombies. While most of the zombies are distracted feasting on William's flesh and the others on Ulrich, Jeremie and Aelita escape to the sewer in the park. The picture then changes to view them running away from the zombies that weren't with Ulrich (William is now a zombie due to being bitten by the rest of the zombie staff), and Yumi pops up and saves them. Back at the school, Ulrich manages to get in a close to the doors. In the Factory, Jeremie goes into the lab and tells Yumi and Aelita to go to the scanner room. The girls are then sent to Lyoko in the Desert Sector. After the virtualization, Jeremie materializes the Overwing. Back in the cafeteria, Sissi and Milly are getting scared when the zombies are huddled in a group. In the park, Kiwi leads the zombies that are with him to the sewer.
On Lyoko, Yumi and Aelita find the activated tower and three Krabs guarding it. Back in the Factory, an alarm goes off on the Factory Interface and he finds out that several zombies lead by Kiwi are in the Factory. In Lyoko, the middle Krab starts to fire at them, but is destroyed when Yumi throws her fan and hits its Eye of X.A.N.A.; then the other two start fire at them and Yumi get hit. In the cafeteria, Ulrich leads a gang to arm themselves as the zombies inter, which causes Rosa to faint again. On Lyoko, they lure one of the Krabs away from the tower, and destroys it. Aelita used Yumi's fan when they were flying over it. Back at the cafeteria, the students and zombies fight but Tania Grandjean is pulled away by Zombie-Jim and the zombified staff and students close in on her and turns her into a zombie with Herb running away. Back on Lyoko, the girls fly up and get shot by Kankrelat and crash down on the ground and the Overwing is devirtualized. Back in the cafeteria, Zombie-William and two other students overpower Herb and turn him into a zombie. Another student is overpowered by the zombified staff and turned into one along with Nicholas. Ulrich, Milly and Sissi are the only ones left. In Lyoko, the third Krab starts to chase them. Yumi then decides to stay behind and fight the Krab while Aelita goes to the tower. She then destroys the Krab by jumping on it back and uses her fan. She then catches up to Aelita. When they get out of the maze, they run into another problem, the ground and the tower has disappeared. Then Jeremie tells them that it's still there and he can see it on the screen, and Aelita uses on of her powers and see the tower. Yumi then says she will telepathically transport Aelita to the tower, to which gives concerns from Jeremie. While in the middle of transporting Aelita, the Kankrelat comes back and shots Yumi, chasing Aelita to fall, but Yumi then ketches her. In the Factory, the Factory Lift opens and Kiwi and the other zombies get out. Yumi then tries to destroy, but misses and she drops the Aelita, but when she tries to pick her back up, she get hit and Aelita then drops to the ground of the sector, but not into the Digital Sea. Yumi is then hit one more time and gets devirtualized. Aelita then runs for the tower and X.A.N.A. virtualizes another Krab. She then runs under the Krab and enters the tower. In the Factory, Jeremie hasn't realized yet that the zombies are in the lab, he does though when Kiwi bites his ankle.
Back in the cafeteria, things aren't going so well. The students that were bitten by the zombies turned into one themselves and Ulrich is attacked by the zombified Odd while the zombies are now surrounding them and nearly turning Sissi and Milly into zombies. Aelita then deactivates the tower and the zombie version of Jeremie uses the return to the past, and time goes back to when their standing waiting for Yumi to join them. When Sissi walks away, Ulrich and Aelita start to complement Sissi, which confuses Milly.
The episode ends with William passing by as Jeremie says, "Yeah, in fact you never can guess a person's true colors, can you?" with the others nodding.
- The original French name for this episode is Contagion.
- Chronologically, this episode takes place after Temptation and A Bad Turn. However, it aired weeks before either.
- When Milly makes the statement "Hey Sissi, what do you think of your father's idea to make a language exchange program with France? Our readers want to know.", it supports the idea that this show does not take place in France for the English version. This was changed to make sense to a USA/England audience, as there are few clues besides the opening & closing credits to elude to it being a French show when translated.
- In the original French dub, Milly says "Sisi, Que penses-tu de la décision de ton père d'organiser des échanges languistiques avec l'Angleterre?", which basically translates to "Sissi, what do you think about your father's decision to organize a language exchange program with England?"
- The episode might be a homage to the 1981 horror film, The Evil Dead, and the Living Dead films, primarily the first film Night of the Living Dead.
- In one shot of when the zombies are attacking Ulrich, Milly and Sissi, Odd is seen on the left, but in the next shot he is seen on the right, right as when he was about to attack Ulrich.
|Code Lyoko: Season 2|
|New Order | Uncharted Territory | Exploration | A Great Day | Mister Pück | Saint Valentine's Day | Final Mix | Missing Link | The Chips Are Down | Marabounta | Common Interest | Temptation | A Bad Turn | Attack of the Zombies | Ultimatum | A Fine Mess | X.A.N.A.'s Kiss | Vertigo | Cold War | Déjà Vu | Tip-Top Shape | Is Anybody Out There? | Franz Hopper | Contact | Revelation | The Key|
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