Code Lyoko: Season 4

Using the data that Franz Hopper gave them, Jeremy and Aelita succeed in recreating Lyoko, which now holds only Sector 5. Soon after, William is materialized, and seems perfectly normal. He shows up at school much to Yumi's delight and Ulrich's disdain. Sissi decides to make herself "editor-in-chief" of Kadic News, much to Milly and Tamiya's dismay. She soon barges into Aelita's room to interview her and is stopped by William. As soon as William makes Sissi, Tamiya and Milly leave, he kidnaps Ae

In order to compensate for William, who is still under XANA's control, Jeremy sets to work designing brand-new virtual attire and digital "enhanced" weaponry and abilities for his friends and recreating the rest of Lyoko. In order to buy himself time to do this, he activates a tower and uses it to create a clone of his own to attend class in his place. Meanwhile, William's absence is drawing attention, from both the principal and his father. While Jeremy's clone is impressing Jim outside, Willia

Jim's nephew, Chris, the drummer of the Subdigitals, pays a visit to Kadic to look for an opening act for the band's next concert. Everybody tries out, and Aelita turns out to be the one Chris is looking for. However, circumstances make sure that Chris does not realize who Aelita is, and XANA's clone of him only complicates matters, kidnapping Aelita and sending her to Lyoko. Jim and Chris manage to involve themselves in their search for Aelita, and end up battling the clone while the rest of th

There is a new recreation room at Kadic and William's clone is put in charge of it. Meanwhile, Jeremy has developed a program to get the real William out of Lyoko. However, the program malfunctions and bugs up the tower, allowing XANA to take it over while Aelita cannot shut it down. As the William clone lashes out at the group, the real William is on Lyoko to keep the tower under XANA's control. Jeremy manages to repair the tower in time for Aelita to reset it, restoring the clone to working or

The new virtual, submersible "submarine" (as Jeremy calls it) is almost complete, the last step being a secondary program that needs to be run by 4 PM the next day. However, when Aelita and Jeremy stay up late to set the program up, they are caught and given detention. Meanwhile, William takes the opportunity to attack the incomplete ship, forcing Yumi to run the Supercomputer in Jeremy's absence. Odd and Ulrich are unable to handle the situation, but Jeremy and Aelita are able to sneak out in t

The gang manages to convince Jeremy to let them test out the Skid. During this test, the navigation system bugs up, leaving the gang stranded in the digital sea. Jeremy runs to his room to fetch the backup programs, but forgets that it's Fire Safety Day and runs into several teachers, eventually having to scale the roof to get to his room. Meanwhile, the Skid stumbles upon another Lyoko and is attacked by two eel-like monsters. Jeremy is able to repair the navigation system and bring his friends

Jeremy decides to teach Odd, Ulrich, and Yumi how to use the Supercomputer in case he or Aelita are unable to, being XANA's favorite targets. During the lesson, Jeremy is attacked by one of XANA's polymorphic clones, leaving the others to operate the Supercomputer without help. Aelita is at the final audition with the Subdigitals, competing against two other candidates, and thus cannot be contacted. To make matters worse, the clone heads for her after dealing with Jeremy. Using what they learned

The group travels to one of XANA's replica sectors in the Digital Sea. Meanwhile, Aelita and Odd get into a fight after Odd's desire to sleep in gets them both in trouble. Furthermore, their arguing inadvertently leads Nicolas and Herb into the factory, where Jeremy is forced to distract them while the group explores the Lyoko copy, which consists entirely of the Forest Sector. On the Lyoko replica, William and a pair of Megatanks arrive to destroy the Skid, the destruction of which would cut th

The group turns to Jim for training, so they can be better prepared to fight against XANA. However, things go bad when XANA possesses a boar to attack them with, forcing them to put their training to good use to avoid it. Furthermore, XANA sends William and a group of Mantas to attack Lyoko's core. Jeremy stays behind to help Jim while the others repel the attack. Jeremy risks his life to save Jim when the two encounter their attacker in a cave, and Aelita deactivates the tower in time to save t

When a comet passes near Earth, XANA uses a laser-equipped military satellite to split it into chunks, simultaneously aiming the bulk of it directly at the factory. Aelita, Odd, and Ulrich are exploring the digital sea at the time, and XANA traps them with a firewall to prevent them from stopping the attack. Meanwhile, Yumi is stuck at school and, when informed of the attack, works to evacuate the school. Jeremy tells Yumi to connect his laptop to an antenna to tap into the military satellite an

Jeremy, Aelita, Ulrich, and Odd go with the rest of their science class on a field trip to an island in the middle of a nearby lake to study water-based plant life. Yumi, not part of the class, remains behind to sit through two important exams. Jeremy's fears about XANA attacking at such an inopportune moment are realized when XANA creates an electricity-blasting sludge that attacks anyone who approaches the shore. Yumi is forced to go to Lyoko alone. She fights William and during their fight is

Hiroki steals Yumi's diary and Ulrich finds it. Meanwhile, in a new attempt to free William from XANA's evil clutches, Jeremy creates a program to find William in the Digital Sea. When he uploads the program to the Skid, the sonar becomes bugged, forcing the gang to return to Lyoko. When the Kongers interrupt their return, Yumi gets stranded, and is lost in the Digital Sea. XANA's attempt to take advantage of this alerts Jeremy, allowing him to direct his friends to Yumi. After fighting off the

Jeremy has finally perfected his "teleportation" process, allowing him to send his four best friends to the location of XANA's supercomputer in the real world to destroy it and leave no trace of their heroic activities. He uses it on Aelita and Odd first, sending them to the jungle laboratory containing the supercomputer. As they explore, they find that XANA is constructing cybernetic spiders with the help of a team of possessed scientists. Before they can stop him, however, William manages to s

Having failed to destroy XANA's supercomputer in the Amazon, the group sets out to finish the job. Meanwhile, Odd's bragging gets the better of him, and he makes a bet with Ulrich not to brag for 24 hours. However, circumstances conspire to constantly put him in the spotlight, and when he ultimately both defeats William single-handedly and destroys the supercomputer in the real world, Odd becomes convinced that being a braggart is something he can be proud of.

Odd tries to take Kiwi to Lyoko, but ends up absorbing him instead. As a result, Odd slowly begins to take on dog traits, such as enhanced smell and scratching himself with his foot. While Jeremy works on separating the two, XANA possesses a biker gang to attack Yumi. When Ulrich and Aelita arrive to Lyoko, they are confronted by William and three Tarantulas. Jeremy manages to split Odd and Kiwi while Aelita deactivates the tower.

Jeremy has developed a program to make the William clone smarter, but the learning curve is still problematic, as it tries to fling a glass into the air from a fork. Milly and Tamiya, overhearing the group's conversation about the clone, decide to ask him personally. The clone, having never been told to keep the information a secret, reveals everything to them, and even takes them to the factory. Meanwhile, Jeremy plans a mission to the next Replika, a copy of the Desert Sector. During the trip,

It's holiday time at Kadic and everyone is headed home. Aelita, however, has no home to go to. As she watches over Lyoko, she gets a message from Franz Hopper, who has constructed a simulation bubble of their mountain home on Lyoko. Though happy to see her father, Aelita quickly learns that the entire thing is a trick from XANA – her father is just an illusion in the simulation bubble on Lyoko. William is there waiting for her in order to throw her in the Digital Sea. However, she escapes result

When Odd breaks a mirror, a little bad luck follows and jinxes him everywhere, even on Lyoko. A bug in his virtual avatar spreads to Yumi and Aelita, causing annoying pauses and random devirtualization in the Desert Replika. Meanwhile, at the site of the Replika's supercomputer, XANA materializes Kankrelats in the real world to stop Ulrich and Yumi. Despite the bug, their mission to destroy XANA's next Replika ends in success, this time by Ulrich, and Odd's luck returns soon afterwards. *This is

Jeremy wins a contest to take a flight in an armed fighter jet, even though it is Odd who entered him into the contest. However, just before takeoff, XANA possesses the jet and sends it to destroy the factory and kill Jeremy by forcing it to crash. As it closes in, Aelita, Odd, Ulrich, and Yumi struggle against William, who devirtualizes them one by one in his attempt to throw Aelita into the Digital Sea. Ulrich is the one to come out on top in a blade to blade fight with William, and Aelita is

When Sissi's pen pal from Iceland, Brynja Heringsdötir, arrives at the school, all the boys swoon over her, making Sissi envious. When Brynja takes an interest in Odd, he ends up showing her the Supercomputer. While there, she messes with the computer despite Odd's pleas not to, creating a glitch in a program Jeremy is installing that causes every virtualization to happen in the wrong sector and prevents materialization. This becomes all the more problematic when William catches Aelita alone on

When Kiwi's mindless destruction becomes too much for the group to bear, they force Odd to keep him at the factory. As Odd drops him off, XANA possesses Jeremy's Kiwi robot, turning it into an army of self-replicating attack dogs. The dogs attack Yumi and Ulrich, among other children, during Jim's Pencak silat class. After Aelita deactivates the tower and a return trip erases the incident, the group decides that the regular Kiwi is not that bad, after all.

Because of a surprise dorm inspection, Odd has to convince Yumi to keep Kiwi at her house. Jeremy, meanwhile, has located the next Lyoko copy, a Replika of Sector 5. Its supercomputer is located on a newly-built space station orbiting Earth. While Odd and Yumi work to disable it, Aelita and Ulrich work to disable the Replika's defenses, which threaten to destroy the Skid. To make matters worse, the supercomputer is guarded by a trio of floating spheres that can grow spikes and melt through metal

Jeremy's cousin, Patrick, comes to visit. Jeremy is not entirely happy about it, since Patrick is "super cool" compared to him. Discovering another Replika, Jeremy and his friends plan a mission to destroy it, leaving Sissi alone with Patrick. She is able to convince him to let Herb rummage through Jeremy's computer files. Herb discovers Aelita's forged documents and the program running the Skid, his efforts to decipher it inadvertently draining the Skid's power. To make matters worse, XANA poss

Aelita's first concert with the Subdigitals is coming up, but Aelita's stage fright threatens to get the better of her. Meanwhile, Odd has to find an extra ticket so he can bring a date. When the concert finally starts, XANA attacks, possessing Sophia, the Subdigitals' manager, in order to kidnap Aelita. He also possesses Milly and Tamiya for some extra help. While Ulrich battles the two reporters, the others work to shut down the tower, all while the Subdigitals' music plays in the background.

Aelita finds a photo of herself with Franz Hopper at the Hermitage, with a mathematical equation in the background. Jeremy discovers that the program works as a reset feature to Lyoko, something not too helpful, but useful nonetheless. Meanwhile, Odd, in an attempt to impress a girl in photography class, inadvertently sends the photo to Sissi, who in turn shows it to her father. He questions the group about it, with Jeremy pointing out that Aelita would obviously be 22 by now if she were the one

Odd is presenting one of his films, but is unhappy because his parents are coming. According to him, they never find fault in anything he does, which he finds dissatisfying, "because he isn't treated like a normal teen." However, when he's finally pressured into it, XANA attacks, using the school's cell phone antenna to spread a virus to everyone who answers their phone to cause them to become vicious, angry, mind controlled slaves, starting with Odd's parents. With the widespread use of cell ph

When an embarrassing picture of Yumi is printed in the Kadic newspaper, she turns to Odd as the source. He manages to get Ulrich to take the blame, however, causing tension between him and Yumi. Putting that aside, Jeremy sets up a mission to the next Lyoko copy, an Ice Replika. Its supercomputer is located in Siberia, where XANA is growing brains for an unknown purpose. Odd and Yumi are sent to the real world to destroy it, only to be confronted by William. When trying to shut down the tower, A

In order to defeat XANA, whom they have vastly underestimated, Jeremy plans to design another multi-agent system to combat him. That, however, is still under development. In more immediate matters, Jeremy has figured out how to free William from XANA, but needs to run his program directly from the Ice Replika's supercomputer. Meanwhile, William's parents visit their son, and the strange behavior of his clone concerns them greatly. Back at the Replika, William and two Mantas come to try to sever

With the Skid gone and XANA's replikas at unmanageable numbers, Jeremy continues work on his multi-agent system. Meanwhile, Aelita has nightmares about her father being killed by XANA. As Jeremy works, he is contacted by Franz Hopper, who arranges a meeting on Lyoko. William wants to help, but all except Aelita are a little wary of trusting him again. William is left in the lab with Jeremy. After meeting up, Franz transmits the data necessary to finish Jeremy's multi-agent system. However, XANA

With their mission completed, the group looks back on all their fond memories of Lyoko. Sissi, meanwhile, plants a tracking device on Ulrich in order to discover their secret. When it comes time to shut down the Supercomputer, all but Yumi are unwilling to go through with it: Aelita is still holding onto the hope that her father can somehow be saved, Jeremy does not want to take away the thing which made them friends, and Odd and Ulrich both liked being heroes. While they muse over their fond at