Code Lyoko Biography
Code Lyoko was first broadcast in the United States as part of Cartoon Network's Miguzi block on April 19, 2004. The series is currently on hiatus on Cartoon Network at the end of the fourth season. Repeat episodes were available on Cartoon Network's video on-demand service and are on Kabillion. Episode 78 ("Lab Rat") was skipped by Cartoon Network, but was shown on Kabillion and on Cartoon Network Australia.
Code Lyoko is about a group of five boarding school students enrolled at Kadic Junior High School: Aelita Hopper, Jeremy Belpois, Odd Della Robbia, Ulrich Stern, and Yumi Ishiyama. The students travel to the virtual world of Lyoko — which is found in a supercomputer housed in the basement of an abandoned factory near the school — to fight against a deadly multi-agent system named Xana.
The artificial intelligence known as Xana is obsessed with world domination. Towards that end, he has taken over the supercomputer in charge of the virtual world of Lyoko, which he largely dominates. Xana is also able to attack the real world by activating towers on Lyoko (usually one at a time), which act as links to the real world. When these towers are activated, Xana is able to seize control of other computers and electrical systems as well as occasionally possessing organic life-forms or generating copies of them. The group has to get Aelita (The only one capable of de-activating towers) to the activated tower(s) out of the forty one scattered about Lyoko's four main regions to deactivate them, neutralizing Xana's attack on the real world.
Once the danger is averted, they can use the supercomputer to return to the past, leaving no one except themselves to remember any of the events that transpired. To complicate the situation, they must do this while ensuring their classmates and teachers are not killed (as going back in time cannot bring back the dead), and deal with the many clashes of personality at the same time. The time travel is programed by Jeremy using a time coordinate system (Which he usually limits to going back one day although there are exceptions) as Jeremy is the only one with the intelligence to understand the supercomputer's workings with the exception of Aelita who has to be on Lyoko to de-activate towers. The jump to the past takes back anyone who has been scanned in one of the scanners. Once back in time, they can use their knowledge of the future to alter events in their favor or the favor of others. This usually entails taking steps to keep one of Xana's attacks from taking place, though they do use the knowledge to prevent other unfavorable events that might not be related to Xana, such as the destruction of Jeremy's Kiwi 2 robot in "The Robots" or preventing Ulrich's humiliation by using prior knowledge of where Sissy hid his notebook and wrote a false love letter from Yumi. However, as a downside, returning to the past adds a qubit to the supercomputer, doubling its power and therefore Xana's with each use.
The five-minute pilot of Code Lyoko, titled Garage Kids, was released in 2001. Though similar in concept, it differs in execution, such as the protagonists possessing their powers in the real world, and some characters not having appearances, such as Sissi, Jim and Aelita.
In the prequel, Jeremie discovers an old abandoned factory containing the supercomputer. He accesses and learns of Lyoko and Aelita, who does not remember her name and is thus called "Maya". Strange attacks begin to occur in the real world as a result of activating the supercomputer. Odd, Ulrich, and Yumi become involved in these attacks, and Jeremie has no choice but to share his secret with them. Odd, Ulrich and Yumi are sent in to stop the force attacking their world. Once the attacks are stopped, the group discovers that they are being caused by Xana, a powerful AI which wants to dominate the world. Aelita remembers her real name when she sees it on the screen in the activated tower and the "Lyoko Warriors" are formed.
The first season of the show has very little plot development. The only major plot developments are made in the two-part finale. The rest of the episodes are mostly filler. Until the finale, each episode consists of the group discovering an attack, stopping the attack, and resetting time to cover it up. Other subplots are included, such as their relationships with one another and other students and teachers at the school. Usually the interaction with their classmates and teachers early in each episode contributes to Xana's attack. Throughout these events, Jeremy works on a program to materialize Aelita in order to shut down the supercomputer safely. He eventually completes the program in the two-part finale, but Xana takes measures to keep Aelita linked to the supercomputer, preventing the group from shutting it down without killing her in the process, leaving a cliffhanger opening for the second season.
The second season, in contrast to the first, is much more plot-focused, though a decent portion of the episodes are still filler. The animation is more realistic and detailed, and Jim and Sissi's personalities have changed significantly, though some traces of their old personalities exist in some form. Aelita lives on Earth in the second season. In the first episode of the second season, she enrolls at Kadic under the name of Aelita Stones. She poses as a cousin of Odd, using a forged birth certificate created by Jeremie. Jeremie's new super scan program also means that Aelita doesn't need to stay on Lyoko to check for Xana's activity; however, due to her links to the supercomputer, Aelita will die if she runs out of Life Points on Lyoko and can only be devirtualized through one of the towers. Aelita also begins having visions of a life she supposedly never lived, and a man named Franz Hopper is shown to have connections to Lyoko. Also adding to the group's troubles is a new student named William Dunbar, who has begun to take an interest in Yumi.
Each member of the group now has vehicles to quickly transport them in Lyoko: Odd gets a hover skateboard called an "Overboard," Ulrich gets a one-wheeled motorcycle called an "Overbike," and Yumi gets a hover scooter called an "Overwing." Aelita can ride any vehicle by herself if necessary, but usually rides with another person. A fifth sector, Carthage, is discovered in Lyoko and turns out to be Xana's home sector, from which all of his data can be accessed, so the group goes on several journeys into this sector to do so. At the same time, Xana begins sending the Scyphozoa after Aelita to steal her memories, and has created three other new monsters, as well. The operations of the supercomputer are also somewhat demystified. Return trips are fewer (though still common) now, because it makes Xana stronger. Eventually, Xana's true purpose is revealed, as are the origins of the supercomputer, Lyoko, and Aelita herself. It is also discovered that the keys to Lyoko are within Aelita's memories, and Xana will be able to escape the supercomputer if it acquires them. In the end, despite the group's best efforts, Aelita's memories are stolen, apparently killing her, but Franz Hopper (revealed to be Aelita's father) revives her and restores her memory. However, Xana escapes the supercomputer, and the group vows to continue fighting against it.
In the third season, Xana has been strangely quiet in both the real world and Lyoko, having done nothing during the group's summer vacation. It still needs a computer to exist, but is no longer limited to a specific one, instead being free to roam the Internet at will. Jeremy has developed a new scanning program capable of tracking Xana, which reveals that Xana appears to be residing in the United States, but lacks the means to strike against Xana. Jeremy's current goal at the moment is to find a way to transfer the group into the Internet.
Because Aelita had her memories returned by Franz Hopper, she can be devirtualized normally. She even has a new power to defend herself within Lyoko — energy fields. Also, Yumi has decided against having a relationship with Ulrich, preferring to remain just friends.
In Carthage, the group finds Lyoko's core, which Xana wants destroyed. Being free of the supercomputer, Xana's attacks are far more powerful. Tower activation is still required to initiate them, but Xana can perform attacks on levels far beyond what he could when imprisoned. Xana can possess mass numbers of people at once, making it that much more difficult for the group to make their way from the school to the factory. In the hopes of isolating the group from Carthage, since destroying Lyoko directly would prove difficult, Xana has turned his sights to Lyoko's sectors, hoping to remove their ability to access Carthage by deleting the sectors they use to get there. By using the Scyphozoa to possess Aelita, Xana can use her to enter the code "XANA" in a passage tower. This gives Xana full access to the sector, after which he can delete it. Despite their best efforts, Xana eventually succeeds in deleting all four sectors. Luckily, Jeremy finds a way to access Carthage directly.
Seeing that their numbers aren't enough against Xana's increasing power, the group decides to add William Dunbar to the team to balance things out. However, a chain of events lead to only Aelita and William being able to make it to his first trip to Lyoko. Once they arrive, the two are separated, and Xana uses the Scyphozoa to possess William. Using William, Xana is easily able to overpower the other Lyoko warriors and destroy Lyoko's core. The act renders the supercomputer useless. Within the empty supercomputer, William is transformed into a dark version of himself, now possessed by Xana to an even greater degree. Afterwards, Jeremy gets a coded message from the internet from none other than Franz Hopper, who has somehow survived the destruction of Lyoko.
In the fourth season, Lyoko is recreated, allowing the group to continue tracking Xana. Traveling into the digital sea in Jeremy's latest creation, a submersible ship called the Skidbladnir, the group finds a number of "Replikas", which are single-sector recreations of Lyoko. Each of these Replikas is controlled by another supercomputer, which is in turn controlled by Xana. To stop Xana once and for all, Jeremy devises a way to materialize his friends at the site of these supercomputers with their Lyoko abilities intact, giving them the necessary firepower to dismantle or to destroy them, all while continuing to battle the Xana-possessed William. The group has new outfits (in both Lyoko and the real world) and weapons to accompany the new season.[1][2]
In the final few episodes of the season, the creation of a monster known as the Kolossus (which destroys the Skidbladnir) opens the gang to realize that with hundreds of supercomputers under his control, Xana cannot be defeated with Jeremie's teleportation method. To this end, Jeremie initiates a multi-agent program to destroy Xana and another program to free William. In "Fight to the Finish", Franz Hopper sacrifices himself to give this program the enough power to destroy Xana and free William. In the epilogue, "Echoes", having completed their mission, the gang shuts down the supercomputer for good.
Source: Wikipedia.org