The episode begins in the Ice sector as Aelita is running toward a tower. She enters it, deactivates it, and is subsequently rematerialized. Ulrich expresses how tired he is of fighting XANA. When Aelita enters the lab, she suggests they go back to Carthage to find data needed for her antivirus. Jeremie disagrees with her, but everyone else convinces him to change his mind. He tells them they'll go tomorrow night. When they leave the factory, it's already late at night. Yumi runs off toward home because she knows her parents will be furious.
Yumi hopes to get home unseen, but her parents were waiting for her the whole time. Her parents keep drilling her on why she gets home so late. They ask her what's wrong, but Yumi says that nothing's wrong, citing her report card as an example. After Yumi goes to bed, her parents agree that they will have to be more strict with her. The next morning, her parents insisted that they walk her to school. When they arrive at the school gates, Sissi mocks her. Later in the day, Yumi tells Ulrich, Odd, and Jeremie about her predicament. Jeremie says she needs to regain her parent's trust and should stay away from Lyoko. Yumi objects, but Jeremie says he'll give her a play-by-play update.
That night, Aelita, Odd, and Ulrich are virtualized into Lyoko's Forest sector. Jeremie materializes their vehicles and they proceed to the edge of the sector. At the sector's edge, Jeremie types in the password:SCIPIO. Immediately, a Transport Orb descends down to Team Lyoko and whisks them away, to the heart of Lyoko. Meanwhile, Jeremie receives a call from Yumi, who tells him that she is thinking of them. After she hangs up, she climbs into a hot bath and sulks. When the three arrive in Carthage, the three-minute countdown begins. Jeremie thinks that stopping the countdown is the key to exploring further. After running down the blue stairs, Team Lyoko reaches a blue room, made up of irregular blocks. Jeremie tells them that Carthage changes its topography whenever someone visits. The three start running, but they end up going around in circles. At an intersection, Aelita tells them to go left, but after she runs in, she gets shot by a Creeper. She backs out of the corridor and Odd destroys the Creeper with his Lazer Arrows. Jeremie tells Ulrich to leave a mark at every fork in the path and go left. If they already see a mark, then they should go right. They follow his advice, but it leads them to a dead-end. Jeremie detects a switch in the room the three just left. The three see the switch, but it's high above them. Odd jumps up to touch it, but he loses all his hit points to laser fire. Ulrich also loses all his life points and the countdown runs out. Suddenly, blue walls rise up on all sides, trapping Aelita. In the lab, Jeremie realizes that Odd and Ulrich haven't rematerialized.
In Yumi's house, everyone is doing their own thing. Yumi and her father are playing Go when she gets a message on her phone. Yumi goes into the hallway and calls Jeremie back. Jeremie tells her to get to the factory as soon as possible. In Carthage, the Scyphozoa is approaching Aelita's position. At Yumi's house, Yumi's mother goes into her daughter's room, only to see an open window and a doll under her bed sheets. Immediately, her parents go to Principal Delmas and Jim to see if they know where she went. Yumi enters Lyoko's Mountain sector. As she approaches the edge of the sector, her vehicle is shot down by Roachsters. She runs to the edge and Jeremie summons the Transport Orb, which takes her to Carthage. In the dormitory of Kadic, Sissi reveals Kiwi, Odd's dog, to Principal Delmas, Jim, and the Ishiyama's. She orders it to track down its master and it runs off. The dog leads them to a manhole in the park and they enter the sewers. In Carthage, as the Scyphozoa gets closer to Aelita, Yumi encounters a network of security lasers. As she tried to get through it, she touched a laser and lost ninety hit points. With only two seconds left, she touches the switch and to countdown stops. In addition, a wall separates Aelita and the Scyphozoa and a pathway opens up for Yumi.
Yumi follows the path to a never-stopping elevator and jumps aboard. She grabs hold of Aelita as the elevator passes by. The elevator leads them to an interface on the outside of the massive blue sphere. Sorting through the data in the interface, Aelita realizes that this is the supercomputer's data and Carthage is where XANA lives. Aelita sends Jeremie the devirtualization codes for Carthage, so that he can materialize Odd and Ulrich. Yumi and Aelita hop onto the Overwing as the Mantas begin to attack. Meanwhile, the adults have reached the factory. Just as Jeremie opens up the data stream, a Manta shoots Yumi and she falls off the Overwing. Aelita takes control of the vehicle and flies it into the data tunnel, arriving in the Mountain sector. She goes to a neutral tower and is materialized through Code: Earth. With the materialization codes for Carthage, Jeremie materializes Odd, Yumi, and Ulrich. When they take the elevator back up to ground level of the factory, the adults are waiting for them. Jeremie presses the switch to take him back down to the lab, but Jim gets in. When the elevator reaches the lab, Jim is stunned by all the technology and forgets about getting Jeremie. Jeremie activates a time reversion, bringing them back to morning. Yumi is being walked to school by her parents. She tells them that she comes home late because she's in love. Yumi walks up to Ulrich, who asks, "What did you tell them?" Her response was, "the truth".
This episode contains examples of:
- As You Know: Jeremie does a similar thing to Ulrich, recounting the exploits of the previous episode to the gang and how important it is to carry on investigating Sector 5.
- Breaking the Fourth Wall: In France, the phrase "You missed an episode" is fairly common way of saying "did you miss something?", but not so much in English, where it just sounds like Odd doing a fourth-wall break, and launching into As You Know to catch up Ulrich and the audience.
- Continuity Nod:
- To False Start:
- Odd brings up the reason to Ulrich why they can't just shut down the supercomputer and call it a day.
- Jeremie tells Jim that he had been in the factory before, just that he may not remember it.
- To False Start:
- Dwindling Party: While death isn't involved, Odd and Ulrich both end up devirtualized and unable to return to Earth. Near the end of the episode, Yumi also becomes a victim, but thanks to Aelita finding the key, the three are able to return with only exhaustion to claim them.
- Exact Words:
- Odd says "something" in response to Jeremie worrying about his materialisation to earth.
- Yumi gets her parents to stop following her around by telling them that she's in love with someone, and has been seeing a boy. When Ulrich asks what she told her parents, she just says "the truth".
- Laser Hallway: Yumi has to backflip, frontflip, and generally dance her way through them, which does slow her down in pressing the button to reset the maze.
- Literal-Minded: A justified example: When Jeremie begs Odd to "Say something," the exhausted purple-wearing boy says "Something..." in response.
- Losing a Shoe in the Struggle: While Kiwi is far from being a villain, he briefly gets into a tug of war match with Jim and one of his slippers, making the gym teacher lose it into the sewer water. Jim goes with one bare foot for the rest of the episode until the Reset Button.
- Malevolent Architecture: Once again, Carthage, the 5th sector. The Lyoko Warriors try and explore the sector as much as they can, but run into trouble with the Scyphozoa taking Aelita hostage, and Odd and Ulrich have to save her by navigating the sector.
- Mobile Maze: The walls change every few minutes, so the team tries to find the key before time runs out. At first, it doesn't end well, but when Yumi comes in to save the day, she stops the countdown.
- Shower of Angst: A variant. Yumi takes a bath, worrying about the fate of her friends (telling Jeremie that she's worried about Ulrich before going into the onsen).
