The scenes written in italics present the scenes that take place in the Simulation Bubble.
The episode begins as the Lyoko Warriors are fighting in the Ice Sector. They are trying to get Aelita to a tower after a not-shown attack, and are being attacked by Bloks. After they defeated them, Odd was doing some dancing as a celebration, missing Jeremie's warning about a Blok sneaking behind him. He gets attacked by the Blok, but he is able to defeat it easily, while telling Jeremie "Hey Jeremie. Next time just enjoy the show and let the real pros get the job done, okay?" Odd then realizes what he just said offended his friends, especially making Jeremie upset. Jeremie launches a return in time after Odd apologizes.
Meanwhile, in a place that seems very similar to the science classroom, Odd is apologizing to Jeremie, who seems to be sulking. Odd and Ulrich are thinking that Jeremie is angry at Odd.
Jeremie, feeling panicked that he has lost his friends (he states that something must have gone wrong during the return trip), asks Aelita if they're still on Lyoko, but she tells him that they're not. To make matters worse, Jim catches him (having snuck into Jeremie's room), and takes him to Mr. Delmas' office.
Meeting with Odd and Ulrich, Yumi has also noticed Jeremie's weird behavior. Ulrich simply states that he's mad at Odd. Yumi then tells them that something strange happened in her English class. Everything seemed to crackle and the teacher repeated her gestures from a few seconds earlier, like a broken record. She wonders if it has anything to do with X.A.N.A..
In his office, the principal asks Jeremie about the whereabouts of his friends. Jeremie tells him he doesn't know and takes a 3-minute break, during which he asks Aelita for help.
Aelita tells him she can hack into the school's computer systems just like X.A.N.A.. Jeremie then takes Mr. Delmas and Jim to the boiler room, saying that his friends are in here. Under Aelita's command, the pipes explode, allowing Jeremie to escape to the Factory.
Arriving in the Factory, Jeremie checks the scanners, only to find that all three of them are empty. By this time, Aelita had an idea of what has happened to the others. She shows Jeremie a sound byte that she recorded of a parallel world (according to her, it was some sort of a radio or TV station transmission). She warns him to be careful while watching it, as it is very weird.
In the sound byte, Ulrich and Odd with other students are doing aerobics, stretching, and push-up with Jim in PE Class.
Jeremie is confused, now that he's seeing himself in the sound byte. Aelita tells him it's probably a recording.
Suddenly, Nicholas hits Herb, who then proceeds to yell at his friend. Suddenly, the two fizzle, rewind, and Herb does the same thing again, just like what happened in Yumi's class earlier. Yumi goes over to Jeremie, who is sitting on the bleachers, immersed with his laptop. She tells him about the weird things going on, and Jeremie informs her he's having difficulty contacting Aelita. She then asks Jeremie why he isn't doing physical education, and he replied that Jim agreed to excuse him. Jim then waves at the two from the track and Yumi sarcastically commands that he is incredible. She becomes suspicious of him.
Jeremie states it's not a tape since he is in it. He then realizes that X.A.N.A. has captured his friends, trapping them in a world created by X.A.N.A. himself. Jeremie valiantly says he will rescue his friends. Aelita doesn't agree with it since it's dangerous. Jeremie, showing his courage, says that he can't leave his friends in the mercy of X.A.N.A.; if the real Jeremie is in the lab talking with Aelita, who is the other Jeremie? Jeremie then says that if he does go into the virtual world, he would much rather do it to find Aelita there waiting for him.
Aelita remotely operates the scanner to virtualize Jeremie.
He is virtualized inside the fake Kadic, which is inside a giant orange bubble that resembles a Guardian. X.A.N.A., in the form of the virtual Jeremie, is at the computer in his room, and notices that Jeremie has arrived (his comments seem to suggest that he had been waiting for him), and dispatches zombie-like versions of Herb, Nicholas and Jim to get him.
In the Ice Sector, Aelita is heading over to the giant orange bubble.
In the meantime, Odd and Ulrich are discussing about Jeremie's strange behavior and Yumi's intuition about it, in which Odd comments that any girls who have a crush on Ulrich is not a normal girl. At that time, Yumi calls Ulrich, who panickly says it's getting worse. Her parents keep doing the same thing over and over again. She decides to go to Factory, without Jeremie (X.A.N.A.) because Yumi doesn't trust him completely. Ulrich and Odd reluctantly agree with her.
The real Jeremie manages to escape the zombies after a long chase and heads for the fake Factory.
In the fake lab, Odd, Yumi, and Ulrich discover that there's no link with Lyoko anymore. Suddenly, X.A.N.A. Jeremie appears, and says that he’s received a message from Aelita that Lyoko is being destroyed and they must get there immediately to deactivate the tower. Yumi, who was suspicious at him the whole time, doesn't want to do it and holds Odd and Ulrich back. At that time, the real Jeremie arrives in the fake lab. He then explains everything to his friends, including X.A.N.A., that X.A.N.A. only wants to send them into the fake scanners to get rid of them for good. X.A.N.A. Jeremie retorts that the real Jeremie is a clone created by X.A.N.A. to buy time and allow Lyoko to be destroyed. Odd, Ulrich, and Yumi stand between the two Jeremies, indecisive.
X.A.N.A. Jeremie asks the real Jeremie how he had arrived there, supposing that it is a virtual world. Jeremie responds that he’s virtualized there in virtual form. X.A.N.A. Jeremie replies that the real Jeremie wouldn’t dare to enter the scanners, stating that he’d be too frightened. But Yumi, Odd, and Ulrich argue that Jeremie would do it if he knew his friends were in danger, now they know which Jeremie is the real Jeremie.
X.A.N.A. becomes enraged at this and transforms into a horrific version of Jeremie. He teleports the zombie versions of Jim, Nicholas, and Herb to the fake lab to kill Yumi, Ulrich, and Odd, respectively, whilst he tries to crush Jeremie with cables summoned from the floor.
Arriving in front of the bubble, Aelita uses her Creativity to destroy the bubble, causing it to explode. As the fake world breaks down, Jeremie is ejected from Lyoko and is devirtualized. After returning to the real world, he goes to the Lab to communicate with Aelita. Ulrich, Yumi, and Odd don't remember anything about the ordeal, but Aelita tells them that she and Jeremie did all they could to set them free, much to the group's surprise when they hear that Jeremie actually came to Lyoko for once. They are then disrupted by a large army of Bloks (which acted as people in the Simulation Bubble), whom they happily fight.
- The original French name for this episode is Canal fantôme.
- This episode marks the only physical appearance of X.A.N.A.
- Certain music heard seems to have been created specifically for this episode, and has not been in any other since.
- This is one of the very few episodes where Jeremie goes to Lyoko. Like the other two episodes (Frontier and Mister Pück), however, his appearance on Lyoko is never shown. In this case, it was due to the simulation bubble X.A.N.A. made.
- There are a couple of music tracks that are heard during this episode that have not been heard until this episode and are rarely heard again, except in a few future episodes, such as the track played during the scene where Jeremie is being shown the sound byte regarding the discovery of the simulation bubble by Aelita, where one of the only times it is heard after this episode is in Dog Day Afternoon when Sissi interrogates the William clone.
- It also appears that throughout the entirety of this episode, during the existence of the simulation bubble, X.A.N.A. did not have a single monster on Lyoko to attack Aelita, perhaps because it was too weak to program all the Bloks, the simulation bubble, and monsters to guard it simultaneously. Like in Distant Memory, although that may not be the case as the simulation bubble in Distant Memory only needed one Blok, X.A.N.A. William, and two Tarantulas to guard it, whereas this one required the entire Kadic Academy to be involved, meaning X.A.N.A. had to use at least 50 Bloks as shown at the end.
- This episode was included in X.A.N.A. Possessed.
- This episode reveals (almost) Full Transfer Cable Route
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