|A Fine Mess|
|Air Date (US)||October 6th, 2005|
|Air Date (France)||December 14th, 2005|
|Written by||Bruno Regeste|
|Storyboard by||Philippe Riche, William Renaud|
|Followed by||X.A.N.A.'s Kiss|
Ulrich is alone in the Scanner Room, flipping a Euro to see who comes out of the Scanners first. He seems to have lost the bet with himself as Yumi comes out first, but immediately afterwards, Odd comes out with Yumi's voice. Yumi speaks with Odd's voice. In the Lab, Jeremie discovers a bug in the materialization program caused Odd and Yumi to switch bodies. He tells them that he may have a solution to this mess by tomorrow morning. Odd/Yumi complains that his/her back itches and says it's the straps of her bra. Yumi/Odd orders him/her NOT to take it off.
The two are uneasy at the prospect of spending the night in each other's life. When they climb out of the sewers into the Park, they ask each other their plans for the day. Yumi/Odd tells Odd/Yumi to act Japanese, not act stupid, eat with chopsticks, and go to bed early. Ulrich asks Odd/Yumi about his plans for the day. Odd/Yumi recalls that he's supposed to break up with Magali De Vasseur and Claire Girard. Later in the day, Ulrich and Odd, who is in Yumi's body, tells Ulrich to practice asking out Yumi on him. Ulrich rejects that action as Sissi comes by. She calls Yumi, whose body Odd inhabits, a string bean. Odd comes back with a comment on her mental capacity and puts his head on Ulrich's shoulder. Disgusted, Sissi walks away as Tamiya Diop snaps a picture of the two together for the school newspaper. Ulrich threatens Odd with death if he does that again and leaves.
In Odd's room, Yumi/Odd fingers through a drawer to get a green handheld device. As she gets it, Kiwi growls at her, knowing that isn't its master. Yumi/Odd gets the object and leaves. In the hallway, Yumi/Odd is confronted by Magali De Vasseur. Magali slaps Yumi/Odd across her left cheek, saying she knows about Claire. Moments later, Claire Girard comes by and slaps Yumi/Odd across her other cheek, saying she knows about Magali. Sissi comes and tells her Ulrich will need a new date once his string bean drops. When she leaves, Ulrich comes in, asking if she got "it". Yumi/Odd asks him what Sissi meant by "string bean". Ulrich tells her it's nothing. As the two walk out of the Dormitory, Milly Solovieff and Tamiya Diop grill Ulrich with questions for the newspaper's gossip section. Ulrich refuses to answer as they walk past.
When Yumi/Odd asks what's going on, Ulrich tells her to ask "that imbecile, Odd". When they reach the Cafeteria, Odd/Yumi asks, "Well, did you find it? I've had it since I was really little." That night, Mr. Ishiyama asks his daughter why she isn't eating. A piece of sushi slips out of Odd/Yumi's chopsticks, much to Odd's embarrassment. Then, he has a flashback in which Yumi hands him the green device, telling him it's only for an emergency. Odd puts down his chopsticks and pulls out the green device. He pulls off the top, revealing the device a large fork for small children. He jams it into a piece of sushi and puts it into his mouth. As he looks around him, seeing Yumi's family staring in disbelief at him, he tells them that he's going to bed and leaves the dinner table. Hiroki declares his big sister's actions as an effect of love. In the bathroom, Odd sees his hands flicker and momentarily become partially transparent, something that obviously shouldn't be happening.
At Kadic, Yumi notices the same effect while stroking Kiwi. Ulrich comes into the dorm room and tells Yumi to be careful as she removes her shoes. When she takes them off, she is overwhelmed by the stench. The next morning, Jeremie, who has been working all night, confirms the problem as a bug in the materialization program. In Ulrich and Odd's dorm room, Yumi wakes up and sees her hands transparent for a moment. At the Ishiyama house, Odd stares at his hands and arms as they flicker. Later in the day, Yumi/Odd describes the symptoms to Jeremie. Jeremie says that all they need to do is restart the materialization program from Lyoko. Yumi stops in disbelief when she sees what Odd has done with her body. Odd/Yumi's orange and lime green clothes contrast sharply against Yumi's normal black clothes. As Yumi yells at Odd, Tamiya stops by again and takes a picture of Yumi's clothes. Milly tells them that these rather scathing pictures will double circulation. Yumi asks Odd again what they mean by love. Odd leaves without answering her question.
In Mrs. Meyer's class, Odd/Yumi is asked by William if she always talks to herself. Odd tells him it's because of a split personality. Faced with a pop quiz on linear functions, Odd asks if he/she can go to the Infirmary. Mrs. Meyer lets him go. He meets up with the others. Jeremie explains that because they aren't in their original bodies, they are unstable. He also says that if they don't deal with it soon, they will disintegrate.
At the Factory, Jeremie virtualizes them into Lyoko. Yumi and Odd, still not in their original bodies, struggle to move in the Ice Sector. As Aelita enters a tower to restart the program, Odd and Yumi's bodies begin to disappear. It's only temporary, but it's markedly worse than before. Faced with a group of Roachsters, they struggle to use each other's weapons. In the tower, Aelita discovers she can't reboot the materialization program from the tower. After Ulrich destroys the Roachsters, Aelita comes out saying they have to get to Sector 5. They take their vehicles to get to the edge of the sector. As the Transport Orb is summoned, Ulrich is devirtualized by a Megatank. The Transport Orb then takes the other three to Carthage.
When they get there, Yumi comments that she feels sick, something normally associated with Odd. They run into the Arena and follow an elevated walkway. Unknown to them, they are being followed by Creepers. They reach a dead-end with the Key situated above an abyss. They see no way of getting to it. A Creeper blasts off Odd/Yumi, but he doesn't fall because XANA has modified gravity. Instead, he floats and begins to swim towards the Key. Unfortunately, he doesn't have enough momentum to reach it. Yumi asks how many life points he has left and Odd tells her plenty. Yumi fires a Laser Arrow at Odd, pushing him enough for him to touch the Key. A door opens up on the side of the room opposite Aelita and Yumi. Odd pushes off, getting to the other side. Aelita and Yumi jump across the abyss, but a Creeper fires at Yumi, pushing her to the other side, but leaving Aelita stuck in the middle. The Scyphozoa arrives to take her memories, but a well-placed Tessen Fan by Odd severs its tentacles. Odd jumps back out and pushes against Yumi to get to Aelita. He then pushes against Aelita to send her flying to the other side. Aelita runs off to the elevator as a Creeper fires at the floating Odd and Yumi. Aelita gets to the computer interface and reactivates control of rebooting the materialization program. He materializes the two as Yumi was about to be devirtualized permanently. Ulrich goes down to the Scanner Room to see that his friends are once again in their original bodies.
At school, Ulrich flips a euro to see whether Odd or Yumi would arrive first. He decides on Odd and he's right. Odd snaps up Ulrich's euro in mid-air and pops it into the coffee vending machine. Ulrich asks Odd if he told Yumi what happened between them. Odd tells him he doesn't plan on telling anytime soon. Yumi walks up, reading the school newspaper and sees the photo spread inside, depicting Yumi with Ulrich. One can only speculate on the extent of Yumi's rage and Odd's suffering for this heinous injustice.
- The original French name for this episode is Désordre.
- Chronologically, this episode takes place after Temptation and A Bad Turn. However it was aired weeks before either.
- When the Lyoko Warriors were running towards the way tower, the tower had a red glow, as if it were activated.
- This episode is the first time the entrance to the core zone in Sector 5 twisted open.