1. Teddygozilla  

First aired: 4/19/2004    Production Code: 101

A student named Milly seeks the comfort of her teddy bear after being embarrassed and ostracized due to her young age by Sissi, the school's bully/diva. Milly believes that her teddy is the only one that she can turn to for comfort and support. A corrupted super computer known as X.A.N.A. enters the real world by possessing the bear. In a quest to strike and destroy his enemies, the X.A.N.A infected teddy bear increases to an enormous size. No one is safe as this monstrosity creates a path of destruction.

2. Seeing Is Believing  

First aired: 4/20/2004    Production Code: 102

When XANA's attack on the nuclear plant endangers the city, the gang must decide whether or not to reveal the secrets of Lyoko to the public and sacrifice Aelita forever.

3. Holiday in the Fog  

First aired: 4/21/2004    Production Code: 103

To keep an eye out for X.A.N.A., Jeremie decides to stay back at school for the vacation. Suspicious of the gang's secrets, Sissi decides to stay as well, milking the situation when X.A.N.A. launches toxic gases into the school, in an attempt to destroy his enemies.

4. Log Book  

First aired: 4/22/2004    Production Code: 104

Sissi has found something very special and dear to Ulrich, his diary! Unfortunately the diary contains some information on X.A.N.A. and Lyoko. Sissi decides to use this as a means of blackmail to get with Ulrich. Later Odd, Ulrich, Sissi, and some of the other students are going to a pool, the bus that their riding in is X.A.N.A.'s next target. He wants to ram the bus into a chemical plant. Now the team must head to Lyoko to help Aelita get to the tower to save the students and the rest of the city.

5. Big Bug  

First aired: 4/23/2004    Production Code: 105

Crashing the city's communications device with a virus, X.A.N.A. jeopardizes thousands of citizens when he runs a pair of trains on a collision course, one of which contains dangerous chemicals. Meanwhile, Odd gets in trouble with the Kadic administration when Sissy reveals the existence of Kiwi to Jim.

6. Cruel Dilemma  

First aired: 4/26/2004    Production Code: 106

Jeremie is working on the materialization program, and accidentally Odd finds it, but it can be used only one time. Jeremie wants to materialize Aelita, but realizes that preparations need to be made. That night, X.A.N.A. possesses two bulldozers and starts to destroy the factory. Odd and Yumi go into Lyoko where she falls into a virtual black hole. In order to save Yumi's life, Jeremie has to choose between either materializing her or Aelita.

7. Image Problem  

First aired: 4/27/2004    Production Code: 107

When a return trip from Lyoko has apparently worn Yumi out, the gang suspects nothing until strange behavior from their friend has them convinced that either XANA is up to something, or Yumi has gone mad.

8. End of Take  

First aired: 4/28/2004    Production Code: 108

When famous director James Finson comes to down to shoot his new movie the gang is shocked to learn that he is filming his new movie in there factory. What will happen when Xana takes control of something completely new and tries to destroy Ulrich and Yumi?

9. Satellite  

First aired: 4/29/2004    Production Code: 109

When all the student's cell phone goes off in class, it starts Sissy on a petition to save her cell phone--but it's goes awry when Odd breaks into the school's office's locker to get his, Ulrich, & Yumi's cell phone. It turns out that X.A.N.A. is trying to get out board a highly powerful military satellite in space. X.A.N.A.'s target turns out be our heroes.

10. The Girl of the Dreams  

First aired: 4/30/2004    Production Code: 110

Around the same time that Jeremie loses contact with Aelita, a new student named Taelia resembling her arrives to Kadic. Believing that Taelia is Aelita with amnesia, Jeremie reveals the existence of Lyoko to her. Meanwhile, X.A.N.A. possesses samurai armor that Yumi had brought to school for a presentation.

11. Plagued  

First aired: 5/3/2004    Production Code: 111

When the gang learns that if Jeremy passes a few tricky quizzes, that he'll get transferred to another school, they quickly seek a way for him to stay, even if it means failing the test on purpose. Meanwhile, XANA gains possession of a pack of rats, using them to attack the flow of power in the city as well as his earthbound enemies.

12. Swarming Attack  

First aired: 5/4/2004    Production Code: 112

Ulrich is fussing over a mysterious letter found slipped under his door one night... a love letter signed by Yumi! Meanwhile, XANA infects a hive of bees and is using it to attack our heroes. Ulrich struggles with his feelings and how to tell Yumi how he feels about her; that is, if he can figure it out himself, and saving the day from XANA in an episode of life and death.

13. Just in Time  

First aired: 5/5/2004    Production Code: 113

The episode starts with Jeremie still trying to materialize Aelita. He calls the team to the factory to show them his latest development: a strand of her hair that he has materialized into a test tube. Unfortunately, he didn't realize that he pressed one button too many, and thus screwed up Aelita's programming by adding in a whole lot of bugs. The result is that, immediately after she successfully enters the code (LYOKO) into a tower, she will be formatted - as in, deleted. And of course, as Jeremie is trying to literally work out the bugs, Xana attacks by putting out shock waves to shake things up, putting Odd, the two junior journalists, and Kiwi in danger. But is Jeremie willing to allow Aelita to be deleted in order to save his friends?

14. The Trap  

First aired: 5/6/2004    Production Code: 114

On the anniversary of their first meeting with Aelita, the gang attempts to find a way to surprise her. Meanwhile, X.A.N.A. sets a trap for the defenders by taking control of the machinery in the factory.

15. Laughing Fit  

First aired: 5/7/2004    Production Code: 115

After Yumi's parents get into a fight, Ulrich decides to use the school play as a way to reunite them. Meanwhile, X.A.N.A. attempts to strike at the warriors by possessing canisters of laughing gas.

16. Claustrophobia  

First aired: 5/10/2004    Production Code: 116

X.A.N.A. short-circuits the Kadic cafeteria in order to trap Odd, Ulrich, and bunch of students in an electrified prison. Jeremie, Yumi, and Aelita race to deactivate the tower before it is too late. Meanwhile, Herb becomes jealous of a new student named Theo who is via for Sissi’s affection.

17. Amnesia  

First aired: 5/11/2004    Production Code: 117

In class learning about nanodoctors, Ulrich is suddenly stricken with a case of amnesia that quickly spreads through the school. When the gang learns that X.A.N.A. is the cause, they rush to Lyoko to prevent this from escalating. Meanwhile, Sissi attempts to persuade Ulrich that the gang is his enemy in an effort to make him hers.

18. Killer Music  

First aired: 5/12/2004    Production Code: 118

A new song Odd downloads sends him into a coma, and the same song is passed through the school. XANA's new beat is the cause, and he can broadcast it anywhere. The hospital is full to bursting with cases, and Odd's heart gets weaker with every beat it makes. But when the tune starts playing in the factory, will the crew learn that music can do more than just soothe the soul? And, will Aelita be able to save the crew? It's all up to a leap of faith...

19. Frontier  

First aired: 5/13/2004    Production Code: 119

Jeremie is now taking his "Materialize Aelita!" campaign to levels unknown - quite literally. Unfortunately that leads to him having a fight with Aelita giving him some guilt. He virtualizes himself to apologize, but there isn't enough memory in the system to complete the transfer, and Jeremie is caught between worlds. It will take more memory than the factory has to complete the transfer back to Earth, and if the crew doesn't hurry, Jeremie will be deleted as an old file! Could this be the final frontier for Jeremie? Will Yumi be able to pick up the slack?

20. The Robots  

First aired: 5/14/2004    Production Code: 120

Both Herb & Jeremie are in a robot competition Herb with "Iron Sissy", and Jeremie with "Kiwi 2." Herb cheats by launching a gear from Sissy to destroy "Kiwi 2." Meanwhile, X.A.N.A.'s latest plan, using the factory to built a robot. Ulrich & Yumi get help from Herb in slow down X.A.N.A.’s robot. Jeremie discovers that X.A.N.A. robot had built in the factory and messed with computer that goes to Lyoko.

21. Zero Gravity Zone  

First aired: 5/17/2004    Production Code: 121

Manipulating the power of gravity, X.A.N.A. prepares to cast his enemies into an airborne grave. Meanwhile, Ulrich is torn between his loyalties to the gang in their fight against X.A.N.A. and to soccer- or rather, his visiting hard-to-please father.

22. Routine  

First aired: 5/18/2004    Production Code: 122

Tired of the same old routine of fighting X.A.N.A., Ulrich decides it's time for a change, which leads to strife between him and Yumi. Meanwhile, X.A.N.A. infects himself with a virus in order to disrupt the scanner program. This will lead the warriors to their death if they can't stop him.

23. Rock Bottom?  

First aired: 5/19/2004    Production Code: 123

In preparation for a secretly-planned dance party at Yumi's house, Odd gets in trouble with the Kadic administration when he covers up the attempted theft of a computer by his friend, Sam. Meanwhile, X.A.N.A. alters the city's earth level in an attempt to bury his enemies.

24. Ghost Channel  

First aired: 5/20/2004    Production Code: 124

When Jeremie and Aelita discover that the rest of the gang is trapped inside one of X.A.N.A.'s virtual prisons, Jeremie must gather his courage and step foot on Lyoko a second time in order to save them.

25. Code: Earth  

First aired: 5/21/2004    Production Code: 125

As Jeremie is perfecting his materialization program for Aelita, Yumi, Ulrich and Odd are making preparations for her arrival. But as success comes within their grasps, Jim's paranoia aggravates the already bad situation started by X.A.N.A.

26. False Start  

First aired: 5/24/2004    Production Code: 126

When Jeremie discovers a fatal connection between a materialized Aelita and the supercomputer, the gang realizes that they will have to postpone their attempts of ridding the world of X.A.N.A. Meanwhile, the corrupted supercomputer decides to engage the warriors in the real world by materializing his monsters for the first time.