List of Code Lyoko: Evolution episodes

Enjoying their normal, thirteen-year-old Jeremy Belpois, fourteen-year-old Ulrich Stern and Odd Della Robia, sixteen-year-old Yumi Ishiyama and 22/23-year-old Aelita Schaeffer soon discover that there is trouble still brewing at Kadic Academy. Even worse, the five best friends discover that their old enemy X.A.N.A. is somehow back as a highly evolved and modified version of itself. In a side story, Ulrich tries to tell Yumi how he has really felt about her all along. However Yumi's enduring platonic friendship with William Dunbar plays on his doubts yet again.

A new, highly intelligent and gifted teenage girl named Laura Gauthier tries to join the quintet at Kadic Academy. She humiliates Jeremy by correcting his mistakes on a complex exercise in class. Aelita suddenly is resentful and suspicious of this new girl, who seems to want to discover their secret.

Meanwhile, Jeremy informs his four friends that he has programmed a new vehicle that is made for travelling through the Cortex easily called the Megapod, and Yumi is chosen as the driver. Unfortunately, Laura follows William to the factory and discovers the lab and Supercomputer, which she is very interested in. During a battle with several Krabs, Aelita, Odd and Ulrich are devirtualized, leaving Yumi trapped in the Megapod. With Laura's help, Jeremy fixes the bugged vehicle and Yumi is returned to Earth just before the Megapod falls into the Digital Sea.

William Dunbar is yet again rejected by the quintet, but when he asks Yumi to come work on their group project she happily agrees, much to Ulrich's disdain. The dislike between the two grows when X.A.N.A. creates a specter of William to attack Yumi, and the two almost have a fistfight in the gym.

Soon after deactivating the tower, another one appears. It's too soon for Odd, Aelita and Yumi to return to Lyoko, so it's up to Ulrich and William to put their differences aside and get Ulrich to the tower to deactivate it. At first the two are showing off and trying to outdo each other, but after William saves Ulrich from falling into the Digital Sea, they call a truce, allowing Ulrich to deactivate the tower. Once back on Earth, William is fully accepted into the group as the sixth Lyoko warrior.

• This is the 100th episode of Code Lyoko as well as the only episode of Evolution to be dubbed in English.

Aelita is determined to discover if her father really is involved in X.A.N.A.'s miraculous and mysterious return. So she, Odd, Ulrich and William go to the Cortex, with Odd piloting the Megapod to help her, while Yumi chooses to stay behind to set up a fundraising party in the gym, enlisting the aid of a shy boy named Remi. He tries to help but accidentally breaks the sound system. Meanwhile, in the heart of the Cortex, the walls start to go haywire and devirtualize Odd and Ulrich, leaving William to save Aelita before he, too, is devirtualized. Back on Earth, they go to help Yumi. Remi is knocked unconscious by an electrical phenomenon and he's replaced by a specter with the ability to create two clones of itself.

Samantha Suarez - Odd's former sweetheart and girlfriend - enrolls at Kadic, and the boy eagerly pursues her. At the same time, he is being pursued by a specter. As an indication of X.A.N.A.'s increasing power, this specter is polymorphic, able to change its appearance at will. The others go to Lyoko to deactivate the tower but are all devirtualized by a giant wall of 121 Bloks. Odd destroys the wall using a scanner eyepiece programmed by Jeremy and deactivates the tower.

Jeremy tries to create a virus to destroy the Cortex, however it doesn't work and the group discusses what to do. They decide to lure Laura to the factory. When she gets there the gang explains about X.A.N.A. and the Cortex and that they need her help, which she accepts to give. She easily fixes the problem and they launch the virus and a return to the past. Laura forgets everything, but thanks to a few hidden commands in the virus, the code for the return to the past was altered to exclude Laura, causing her to start having memory flashbacks of her time in the lab. She follows the memories to the sewers. William (who was left on Earth) tries to stall her, but fails, and Laura ends up back at the lab.

Jeremy and Aelita program false source codes that will destroy any specter that tries to take them from a Lyoko Warrior, and tests it using Ulrich as a guinea pig. Ulrich is told to wait at school until he spots a specter and deliberately touch it to transfer the fake source codes to it to test if they work.

The gang return to the Cortex to get data on the mysterious Ninjas. Ulrich opts out of the mission because he has a karate competition to attend, and Jim won't let him skip it. The others don't fare well against the Ninjas until Ulrich arrives, offering them advice that Jim passed on to him: be unpredictable. With the advice given by Ulrich, and a new bo staff weapon programmed for Yumi, she manages to defeat the three Ninjas easily and gathers the data. In it they find a video clip of Professor Tyron addressing several humans dressed in ninja-like costumes.

Jeremy is woken up by the Superscan when it picks up two activated towers. He warns the others, and just as they're leaving Aelita receives a message from an unknown sender asking her to meet them in a nearby building. While she's thinking about it, Laura comes and says she heard Aelita's phone ringing. Aelita tells her there's an alert and she should go on ahead to the lab, which she happily does.

Aelita then goes to the meeting place and finds a blonde-haired woman there; her long-lost mother, Anthea. They share a warm mother-daughter embrace. Jeremy offers Laura the controls and goes to find Aelita, realizing her "mother" is actually a specter, and tries to convince her of it. Aelita doesn't believe him and returns to the specter.

A computer error causes the science test scores at Kadic to be messed up, as well as bugging up the rest of the computer system with it. Jeremy is alerted to an activated tower and he, Aelita, Odd, Ulrich and Laura go to the lab to check it out. Laura's dad is called to the school as a result of the marks mix-up and he calls her back to the principal's office. He expresses his doubt in the school's ability to help his daughter achieve the highest level, and decides he wants her to transfer to another school. Laura insists on staying, deciding to show him the Supercomputer as proof of what Kadic can offer her.

It's Friday the 13th and Odd can't believe his luck - he's won the lottery! He tries to impress Samantha with this fact, but he doesn't manage to catch up to her in time. Jeremy discovers that the lottery wins are happening all over Europe, and realises that it must be X.A.N.A.. The group minus Odd head to Lyoko to deactivate the tower in Sector 5, which they do successfully. They return home and Odd comes to the lab feeling gloomy about not actually winning the lottery and his situation with Samantha, having bought a thousand red roses to give to her thinking he truly had won the jackpot.

Jeremy then notices that X.A.N.A. had used the tower as a diversion to attack the Skid with a virus while they weren't looking. Odd is the only one who can go in and must pilot the bugged-up Skid and try to counter the virus with little experience doing either. Laura is called in to help, but they don't make much progress. Jeremy then decides to virtualise Laura into the Skid to help on site, and she becomes extremely excited about the idea. Aelita, however, quickly guides Odd through the steps and together they counter the virus just before Laura is about to be transferred. The Skid is returned to normal and Laura leaves, furious about not having to go to Lyoko after all.

The gang has planned a routine data gathering mission in the Cortex. However, Ulrich opts out of the mission when he finds out that Yumi wrote some negative things about him. While in the Cortex being attacked by Ninjas, Yumi can't stop thinking about Ulrich. She gets herself devirtualized on purpose just to go talk to him and work things out. The two soon reconcile.

A tower is activated and a specter is sent after Odd, taking the appearance of a football player. Aelita and Ulrich go to deactivate the tower, but when they reach it, Aelita is unable to enter. The tower deactivated itself because Odd lost the last of his source codes to the specter.

Odd then formulates a protection plan where the "no-coders" protect the people who can't return to Lyoko for 12 hours, and who have nowhere to hide from X.A.N.A.'s specters. William is particularly annoyed at Yumi and quickly becomes fed up with Odd's plan and being referred to as a "no-coder," and he storms off. Another tower is activated and Ulrich and Aelita are shut in a closet under Odd's protection while Yumi calls a truce with William so they can go to Lyoko. When he and Yumi reach the tower they're confronted by an evil clone of William who plays on his doubts, telling him that he's being used by the gang, especially Yumi. He and the clone then chase after Yumi while the footballer specter finds Ulrich and Aelita and corners them.

Towers are being activated and deactivated constantly and X.A.N.A. is trying and failing to send specters. Laura follows the group to the lab and Jeremy allows her to help, seeing as it's an unusual case. While in the lab she asks Aelita about Franz Hopper. Not getting a decent answer, she goes to do research in the library before confronting Aelita, saying that she knows Franz built the Supercomputer, and that he apparently abandoned his daughter. Aelita replies that her father didn't abandon her, but selflessly sacrificed himself for her, and asked Laura if her own father would do the same for her. Aelita returns to the lab.

A man named Graven shows up at Kadic asking after Jeremy, the smartest kid in school, offering him a place in a special scientific institution specialising in quantum physics. Jeremy denies having any knowledge of the subject, then figures out that Graven is an agent sent by Tyron, and that they must have traced Lyoko's location on Earth somehow. Graven gives up on Jeremy and moves on to Laura, the second smartest in the school.

Aelita sends the others to Sector 5 to search for any kind of tracking device that the Ninja from episode 14, Stowaway, could have planted while it was on Lyoko. They find it but don't manage to destroy it, as when it's damaged it sends out an electromagnetic pulse that causes the Lyoko Warriors pain and threatens to damage the Supercomputer. They decide to dispose of it in the Cortex, carefully removing it from the bottom of the platform and taking it to the Replika in the Skid. X.A.N.A. retaliates in the Digital Sea by sending Kongers, but they manage to make it there.

Aelita dreams of her long-lost mother, Anthea. She wakes up and goes to see Jeremy, but finds Laura there with him, working together on the virus to destroy the Cortex. A hurt Aelita leaves, and Laura smugly denies that there was anyone at the door. Jeremy and Laura finish the virus and the group plans to implement it that afternoon, but Odd gets detention and Ulrich sprains his ankle, forcing both of them to opt out. William, Aelita and Yumi go in.

Thanks to Odd, Jeremy comes up with the idea of getting source codes back from specters, thus reducing X.A.N.A.'s power. The plan works and they trap a specter, but things go horribly wrong when it ends up on Lyoko in the form of blackish-green particles, severely damaging and disabling the scanners and putting the Lyoko Warriors it touches into a coma-like state.

Jeremy can't bring the others back or even send William to help because of the damage to the scanners. The specter then tries to throw Yumi into the Digital Sea. Odd enters the Desert Way Tower and Jeremy uploads the codes they stole from the specter into him. Odd races to the activated tower with the specter in hot pursuit. He enters the tower and the specter goes in after him, but he manages to deactivate it before the specter touches him.

Meanwhile Aelita resorts to social networking to try to find her mother. After the mission Jeremy tells her the good news: they were able to steal 4% of X.A.N.A.'s power and Odd is capable of deactivating towers again. Aelita then tells Jeremy her good news: she is getting hundreds of responses about her long-lost mother as hundreds of people all over the world join the effort to find Anthea Schaeffer.

• This is the only episode that shares a title from the animated series

Jeremy manages to develop a program that will allow the gang to hack Tyron's surveillance system and spy on him, both using video and sound, and potentially speak to Anthea. When the gang go to the Cortex to implement it, all but Aelita are devirtualized by Ninjas when they tip off an unforeseen security system. Aelita opts to stay in the Cortex's core to wait for her mother to appear, asking for a clone to replace her at the school while she's gone, which causes enough problems of its own.

Aelita confides in Yumi that she's feeling depressed because her mother still hasn't attempted to contact her. Yumi suggests they have a girls' day out to take her mind off things and Aelita accepts, but Sissi decides to invite herself along as well. When a tower is activated Sissi refuses to leave their side, so Yumi heads for the lab while Aelita is forced to return to the school and keep Sissi occupied.

Laura and Jeremy finally finish their virus. Laura is keen to implement it immediately and destroy both the Cortex and X.A.N.A., but Jeremy insists they wait until Aelita has made more progress with her mother, Anthea. Meanwhile William feels neglected after Yumi tells him she's too busy to read a book he offered her. Laura takes the opportunity to try and recruit William for her cause, and after some persuading he hesitantly agrees.

It's Aelita's "birthday" and someone is trying to hack into the supercomputer. The firewalls Jeremy created manage to stop it from getting in. When analyzing the data packet sent, Jeremy notices that it is of unusual design: created by Franz Hopper. Perhaps Anthea is trying to contact them to wish her daughter a happy birthday. Jeremy calls the others but does not alert Aelita, as he wants it to be a surprise.

During a training mission on the Cortex, the Megapod bugs up and Jeremy is forced to figure out how to repair it. Just as he does so, the superscan finds an activated tower on the Cortex. But when they arrive on site, they find the tower has a purple halo. It has been activated by Tyron, and the Lyoko Warriors are soon surrounded by Ninjas, and Odd, Aelita and Ulrich become trapped in a temporal bubble that sends them back to that morning's gym class, repeating it dozens of times over. They must find a way to contact Jeremy to tell them what happened so that he can destroy the bubble before Tyron uses its signal to track their location on Earth.

A mission to gather more information on Aelita's mother is cancelled when X.A.N.A. launches another attack in the Mountain Sector. Unable to warn Odd and Ulrich, the two boys become the targets of X.A.N.A.'s attacks. Odd loses all of his codes once again. Meanwhile Aelita and Yumi are pinned in the Cortex by X.A.N.A.'s forces en route to deactivate the tower, and Yumi is later devirtualized.

On Earth, X.A.N.A. has stolen Ulrich's codes as well. Realizing that Yumi is on Earth too, X.A.N.A. sends the specter to find and recover the codes. Odd is sent to provide William and Aelita with backup while Ulrich goes looking for Yumi. After arguing with Jeremy over Yumi's safety, William devirtualizes himself in order to find her. Odd goes to Lyoko while Aelita is being pursued by Kongers in the Digital Sea. After Ulrich calls Yumi to ask where she is, she's spotted by the specter. William and Ulrich team up to go look for Yumi, but split up after finding her phone lying abandoned on the ground. While on Lyoko, Odd is pinned down and out of ammunition, the Bloks are pushing him towards the Digital Sea. Aelita shows up in the Skid and destroys all the monsters.

Aelita insists they destroy the Cortex right away and they set out on what should be their final mission. But due to interference from X.A.N.A., they don't even make it inside the Dome; the mission is a failure and they're forced to wait twelve hours before they can try again. As she's on her way back to the lab for their second attempt of finally exterminating their longtime virtual enemy once and for all, Aelita is called to the principal's office where she finds Tyron waiting for her. He reveals that he's been married to Anthea for four years now, making him her stepfather. He gives her Anthea's locket and shows her a digital message a happy Anthea left for her, telling Aelita she can completely trust Tyron to reunite them. He then tells Aelita to call off the mission to destroy his Supercomputer or else she'll never see her mother again, but Aelita refuses and escapes. After finding out the locket contains a tracking device, Yumi takes it and stays at the school while Aelita goes to join Odd, William and Ulrich on the Cortex. Tyron apprehends Yumi and then orders for his Supercomputer to be shut down. The virus is successfully transferred to his Supercomputer but it doesn't have time to take effect before the machine is shut down. Aelita and the others barely manage to escape in time and make it back to Earth.