The BEST Episodes of Code Lyoko
Every episode ever - ranked by fan votes!
Last Updated: Jan 7, 2020
Network: Cartoon Network
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.
#1 - A Bad Turn
Season 2 - Episode 13 - Aired Nov 16, 2005
Ulrich and William battle to impress Yumi during Drivers Ed at school, but they must find a way to put aside their differences and work together when XANA unleashes an army of Krabes in the real world.
#2 - The Pretender
Season 3 - Episode 6 - Aired Oct 14, 2006
Yumi's classmate Johnny has a crush on her and won't let her out of his site, making it hard to help her friends battle the swarm of birds XANA sent to attack them. When she gets hurt the warriors must go back in time in order to save her.
#3 - Exploration
Season 2 - Episode 3 - Aired Sep 14, 2005
Our heroes discover Sector 5 and seek to uncover some of its secrets, but first they must overcome its many traps. Meanwhile, Yumi's parents decide to visit, and she has a tough time getting away in order to help her friends in Lyoko.
#4 - The Chips Are Down
Season 2 - Episode 9 - Aired Oct 26, 2005
When he learns Yumi may be leaving, Ulrich secretly goes back in time, in order to help her family, even though he knows this will make XANA stronger. Jeremy and Yumi decide he's gone too far and consider removing him from the group.
#5 - Sabotage
Season 3 - Episode 9 - Aired Nov 2, 2006
When Xana sabotages the supercomputer, weird bugs begin cropping up in Lyoko. Since the attack keeps draining power from the supercomputer, Aelita purposefully wipes out The Ice Sector leaving The Mountain Sector left.
#6 - Attack of the Zombies
Season 2 - Episode 14 - Aired Nov 23, 2005
When Xana possesses Kiwi, it turns the little dog into the carrier for a virulent virus that turns those it infects into zombies. Aelita and Jeremie are stuck in the cafeteria and Odd is a zombie himself. Jeremie and Aelita escape but Ulrich and the other students fight the rest.
#7 - Fight to the Finish
Season 4 - Episode 29 - Aired Nov 10, 2007
In the ultimate battle against XANA, our heroes work with Franz Hopper to destroy the evil super computer forever. But first they must face everything XANA can throw at them.
#8 - Distant Memory
Season 4 - Episode 17 - Aired Aug 31, 2007
While everyone is gone for the winter holidays, Aelita stays behind to watch for XANA. But she receives a message from her long-lost father inviting her to join him in the virtual world, and she accepts, realizing too late that it's a trap.
#9 - Cousins Once Removed
Season 4 - Episode 23 - Aired Oct 13, 2007
Jeremy's cousin Patrick visits and problems arise when Patrick lets Herve look at Jeremy's computer. Our heroes' mission is soon compromised and Aelita's fake identity is uncovered. Only a trip back in time can fix this situation.
#10 - Wrong Exposure
Season 4 - Episode 25 - Aired Oct 27, 2007
Aelita's secret past is in danger of being revealed when Sissi gets a hold of an old photo of Aelita with Franz Hopper. Meanwhile, Jeremy needs the picture because of the mathematical formulas written on the blackboard in the background.
#11 - Frontier
Season 1 - Episode 19 - Aired Jan 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.
#12 - The Key
Season 2 - Episode 26 - Aired Feb 8, 2006
Jeremy discovers the missing key to the link between Aelita and XANA. If they can get the missing piece from XANA, they can destroy him for good. But the evil super computer is ready for the ultimate battle to save itself from destruction.
#13 - Mister Puck
Season 2 - Episode 5 - Aired Sep 28, 2005
Aelita's frightening visions at the Hermitage lead her to a strangely familiar plush toy. But when the toy is accidentally torn, a key is found, leading to a locker containing Franz Hopper's encrypted journal.
#14 - The Robots
Season 1 - Episode 20 - Aired Jan 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.
#15 - Teddy Gozilla
Season 1 - Episode 1 - Aired Sep 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.
#16 - Franz Hopper
Season 2 - Episode 23 - Aired Feb 1, 2006
A man claiming to be Franz Hopper shows up at the computer lab and blames Jeremy for destroying his diary - the only hope of defeating XANA. With everyone now mad at Jeremy, XANA acts quickly to lure Aelita back to Lyoko.
#17 - Code: Earth
Season 1 - Episode 25 - Aired Feb 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.
#18 - Just in Time
Season 1 - Episode 13 - Aired Nov 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.
#19 - New Order
Season 2 - Episode 1 - Aired Aug 31, 2005
After discovering Aelita's link to the supercomputer and the inability to shut it down, Jeremie works hard to find new and better ways to fight Xana. He develops new vehicles for the group and new tower-scanning program that instantly detects activated towers, allowing Aelita to live on Earth. The class takes a trip to the nearby woods for a scientific field trip. Ulrich wants to partner up with Yumi, but she's already partnered up with someone named William.
#20 - A Great Day
Season 2 - Episode 4 - Aired Sep 21, 2005
XANA gains the ability to go back in time and our heroes discover this power also makes him stronger, to the point where he can now control human beings. After XANA possesses Sissi, the heroes realize they must take action quickly.
#21 - The Trap
Season 1 - Episode 14 - Aired Dec 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.
#22 - Triple Trouble
Season 3 - Episode 11 - Aired Nov 6, 2006
Jeremy gives Odd the ability to teleport himself across short distances within Lyoko, but the initial test results in three Odds being created. The clones don't get along so well and have split up in town while XANA launches a new attack.
#23 - Crash Course
Season 4 - Episode 7 - Aired Aug 20, 2007
Jeremy tries to teach his reluctant friends how to operate the computer in order to enter Lyoko. While Aelita is away at a music audition, XANA launches an attack and renders Jeremy unconscious, leaving the others to remember their lesson.
#24 - A Lack of Goodwill
Season 4 - Episode 16 - Aired Aug 30, 2007
Our heroes travel to the desert to destroy a hidden super computer but their trip is cut short when the real William arrives in the computer lab. Meanwhile, Jeremy tries to prevent William's clone from being discovered by Milly and Tamiya.
#25 - Saint Valentine's Day
Season 2 - Episode 6 - Aired Oct 5, 2005
Aelita receives a necklace which she believes is from Jeremy but is actually a poisoned gift from XANA. She puts it on and becomes powerless to resist the urge to go to Lyoko where XANA's trap awaits her.