The BEST episodes of Code Lyoko season 1

Every episode of Code Lyoko season 1, ranked from best to worst by thousands of votes from fans of the show. The best episodes of Code Lyoko season 1!

Code Lyoko tells the story of a group of students who uncover a parallel universe called Lyoko inside a super-computer, which entraps a malevolent sentient AI called X.A.N.A.

Last Updated: 12/13/2024Network: France 3Status: Ended
Code: Earth
star
7.79
19 votes

#1 - Code: Earth

Season 1 - Episode 25 - Aired 2/18/2004

Jeremie finally completes his materialization program and prepares to bring Aelita into the real world. At the same time, Jim's suspicions of the group have risen to the point that he's actively trying to discover their secret and he ends up causing Jeremie to injure his ankle while running away from him down stairs in the school.

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Frontier
star
7.68
19 votes

#2 - Frontier

Season 1 - Episode 19 - Aired 1/7/2004

When Jeremie yells at Aelita, he tries to go to Lyoko to apologize. Unfortunately, while Yumi is transferring him, she makes a scanner error, which leaves him trapped in a virtual limbo between Lyoko and the real world, so Aelita has to retrieve data to recover Jeremie without support in order to bring Jeremie back, but when she gets to the Mountain Sector, there are a couple of Blocks guarding the tower.

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False Start
star
7.53
17 votes

#3 - False Start

Season 1 - Episode 26 - Aired 2/25/2004

Aelita's materialization program has worked, and she's now living on Earth. When Jeremie pulls the plug on Lzoko, Aelita faints. Jeremie believes that a virus was given to her by X.A.N.A. while he was bringing her to Earth which has linked her to the supercomputer, preventing the group from shutting it off. X.A.N.A. brings his Roachters into the real world in mass numbers and unleashes them on the school.

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The Robots
star
7.48
48 votes

#4 - The Robots

Season 1 - Episode 20 - Aired 1/14/2004

During a school robot competition, X.A.N.A. sends a robot of his own to deal with the group. Ulrich and Yumi are forced to enlist Hervé's help to destroy it while Jeremie and Odd head to the factory to deactivate the tower.

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Just in Time
star
7.41
22 votes

#5 - Just in Time

Season 1 - Episode 13 - Aired 11/26/2003

Jeremie materializes a single hair of Aelita's. Meanwhile, different parts of the school begin to crumble apart. Jeremie learns that his first test damaged Aelita's program, and she'll be deleted if she tries to deactivate a tower. On top of that, they learn that X.A.N.A. is responsible for the damage being caused to the school by using ultrasonic sound waves, which continues to get worse.

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The Trap
star
7.30
20 votes

#6 - The Trap

Season 1 - Episode 14 - Aired 12/3/2003

It's been a year since the group first discovered the supercomputer and Aelita, and they decide to throw a surprise party for Aelita. Sissi catches wind of the party and follows Ulrich and Yumi to the factory. On the way there, X.A.N.A. possesses the factory as a whole. X.A.N.A. traps Ulrich, Yumi and Sissi in the elevator and drops them to the bottom of the shaft.

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Ghost Channel
star
7.29
48 votes

#7 - Ghost Channel

Season 1 - Episode 24 - Aired 2/11/2004

After battle against X.A.N.A. Ulrich, Odd, and Yumi are nowhere to be found. They, however, do not see anything wrong with where they are. X.A.N.A. has trapped them in a world of its own design, which is fashioned after the school to ease their suspicions. However, the world that Ulrich, Odd, and Yumi are in appears to have some glitches in it. Jeremie virtualizes himself into that world to save the others.

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The Girl of the Dreams
star
7.23
22 votes

#8 - The Girl of the Dreams

Season 1 - Episode 10 - Aired 11/5/2003

After Jeremie fails zet again to materialize Aelita, a student Taelia arrives at school that looks exactly like her. Jeremie is convinced that it must be her. The others aren't quite as convinced, but Jeremie insists that the materialization process must have caused her to lose her memory. X.A.N.A. possesses the samurai armor that Yumi brought to school and sets it on the group to chase them.

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Swarming Attack
star
7.21
19 votes

#9 - Swarming Attack

Season 1 - Episode 12 - Aired 11/19/2003

After failing with an army of rats, X.A.N.A. attempts a similar tactic using hornets. Meanwhile, Ulrich gets a letter from Yumi saying that she loves him. He's not quite sure how to respond, so he avoids talking to her about it.

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Routine
star
7.21
19 votes

#10 - Routine

Season 1 - Episode 22 - Aired 1/28/2004

After many X.A.N.A. attacks in a row, Ulrich starts to get tired of fighting. He also questions his relationship with Yumi and if she feels the same way about him. X.A.N.A. activates a tower without disturbing Earth, Jeremie forces Ulrich, Odd, and Yumi all to go to Lyoko to deactivate the tower. After being virtualized, a virus infection occurs on Lyoko because X.A.N.A. sabotages the Devirtualization Program, meaning if the group is devirtualized, they will permanently perish.

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Big Bug
star
7.13
54 votes

#11 - Big Bug

Season 1 - Episode 5 - Aired 10/1/2003

X.A.N.A. manages to disable much of the city's infrastructure. Two trains that are completely automatic are put on a collision course, one of which contains a load of highly and deadly toxic chemicals. Yumi and Ulrich go to help Aelita, but Odd is forced to stay because Sissi tells on him to Jim for having Kiwi since he pulled a prank on her.

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Log Book
star
7.09
55 votes

#12 - Log Book

Season 1 - Episode 4 - Aired 9/24/2003

Sissi finds and steals Ulrich's diary, so he is blackmailed into being her boyfriend. During a trip to a swimming pool, Jeremie and Yumi have the opportunity to find it. The new electric bus that is being used for the field trip is possessed by X.A.N.A. and starts acting weird as a result.

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Killer Music
star
7.05
20 votes

#13 - Killer Music

Season 1 - Episode 18 - Aired 12/31/2003

When X.A.N.A. creates an MP3 file that puts anyone who listens to it into a coma, Odd ends up being the first victim. Soon, the rest of the city begins to follow, including Ulrich and Jeremie.

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Cruel Dilemma
star
7.05
20 votes

#14 - Cruel Dilemma

Season 1 - Episode 6 - Aired 10/8/2003

Jeremie's materialization program for Aelita is finished, but is only good for one use. In turn, X.A.N.A. possesses two bulldozers and sets them on the factory to prevent Aelita's materialization from taking place. Odd goes to Lyoko while Ulrich tries to stop the bulldozers.

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Holiday in the Fog
star
7.04
25 votes

#15 - Holiday in the Fog

Season 1 - Episode 3 - Aired 9/17/2003

After Jeremie and Ulrich paint funny graffiti of Jim on aschool wall, Sissi overhears him talking about X.A.N.A. She gets her father to let her stay there during the vacation so she can discover the group's secret. X.A.N.A. takes the opportunity to possess several barrels full of poison and turns the poison into a deadly, living gas.

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Teddy Gozilla
star
7.02
41 votes

#16 - Teddy Gozilla

Season 1 - Episode 1 - Aired 9/3/2003

Milly and Tamiya are doing a report on the school prom. Milly tries to ask Ulrich out, and he turns her down because he's going to the dance with Yumi. Upset, Milly storms off. X.A.N.A. possesses her teddy bear, turns it roughly twostories high and uses it to attack those who had made fun of her.

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Satellite
star
7.02
51 votes

#17 - Satellite

Season 1 - Episode 9 - Aired 10/29/2003

During class, everyone's cell phones suddenly go off, and all of them are confiscated. Sissi is not happy about this and organizes a protest in response. Yumi joins the protest, since having cell phones is a necessary part of the group's fight against X.A.N.A. X.A.N.A. is using the school's antenna to take over the nearby television antenna. From there, he could take over a laser-equipped, military satellite.

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Image Problem
star
7.00
21 votes

#18 - Image Problem

Season 1 - Episode 7 - Aired 10/15/2003

An unexplained incident on Lyoko ends up devirtualizing Yumi without any cause, she is taken to the infirmary. After waking up, she attacks Yolanda and continues to act weird wanting to go to Lyoko. Jeremie won't let them, cause he wants to know what caused her devirtualization. On Lyoko, Aelita finds several Roachters guarding an orange sphere-Guardian, and informs Jeremie.

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End of Take
star
6.95
19 votes

#19 - End of Take

Season 1 - Episode 8 - Aired 10/22/2003

Famous director James Finson announces that he plans to make a movie in the city, using the factory as their primary location. Ulrich tries to convince Finson that making a movie there would be a bad idea. X.A.N.A. possesses the alien monster prop and uses it to capture Ulrich and Sissi and use them as bait for the others.

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Plagued
star
6.95
19 votes

#20 - Plagued

Season 1 - Episode 11 - Aired 11/12/2003

X.A.N.A. possesses a rat that tries to sneak a bite from the school's kitchen. His creation goes on biting other rats, putting them under his control. Meanwhile, the school counselor has been watching Jeremie and believes him to be a gifted student. As such, he believes that Jeremie would be better off at a more advanced school and decides to give him an aptitude test. During the test, X.A.N.A.'s rat army attacks the school.

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Rock Bottom
star
6.88
17 votes

#21 - Rock Bottom

Season 1 - Episode 23 - Aired 2/4/2004

During a vacation period at the school, the group plans to have a party at Yumi's house. Odd promises to have a DJ at the party. This DJ, named Samantha Knight, is also his girlfriend, who goes to another school. After meeting up, she has Odd take her to the computer room. Once they arrive, she tries to steal a laptop, since she's too poor to afford one. Odd stops her, but ends up being caught by Jim. Meanwhile, X.A.N.A. causes the ground under the city to melt, making all the buildings sink.

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Claustrophobia
star
6.88
49 votes

#22 - Claustrophobia

Season 1 - Episode 16 - Aired 12/17/2003

Theo takes an interest in Sissi, Hervé becomes jealous and tries to get him expelled. X.A.N.A. possesses the cafeteria during lunch, trapping most of the students inside its electrified walls. Jeremie and Yumi leave the cafeteria before this takes place. Now Yumi has to get Aelita to the tower by herself before the cafeteria collapses in on itself.

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Laughing Fit
star
6.78
18 votes

#23 - Laughing Fit

Season 1 - Episode 15 - Aired 12/10/2003

In class, Susan teaches the class about nitrous oxide, more commonly known as laughing gas, and its effects. It can be dangerous if not neutralized by water quickly. During a school production of Romeo and Juliet, X.A.N.A. possesses the laughing gas in the science room and uses it to attack the gang so they would laugh themselves to death.

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Amnesia
star
6.68
19 votes

#24 - Amnesia

Season 1 - Episode 17 - Aired 12/24/2003

When Susan gives a lesson on nanotechnology, she has small machine designed to produce the little robots as an example. X.A.N.A. has infected the machine, so when they find it filled with gel, Odd carelessly ends up pushing Ulrich's face into a small scoop of it. Later on, Ulrich gets a headache and faints. When he wakes up, his memory is gone.

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Zero Gravity Zone
star
6.67
18 votes

#25 - Zero Gravity Zone

Season 1 - Episode 21 - Aired 1/21/2004

Just before an official school soccer game, X.A.N.A. starts nullifying gravity by creating electromagnetic fields around specific areas. Ulrich is unable to help stop X.A.N.A. this time around, instead needing to impress his parents, who will be attending the game. The others have to stop X.A.N.A. before the entire school is sent into orbit.

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