PlotThe episode begins with another of Aelita’s visions. In it she's entering the Hermitage and inside she meets the Men In Black. She then wakes up screaming in her bed. She goes to the bathroom to wash her face and is confronted by Sissi who heard her scream. Aelita then starts crying and Jim comes and asks Sissi what is going on. She explains that Aelita is not feeling well, but she gets really nervous when Jim asks her why she is still up. Jim takes Aelita away and when they pass Jeremie’s room, he wakes up and asks Aelita what happened. She tells him that it was nothing. The rest of the children in the hall peek out. Jim tells them all to go back to sleep, and all the lights go out.
The next day she explains the dream for the gang, both Yumi and Odd think it was just a nightmare. Yumi then asks Odd about his Internet dating, and he says that he has met an amazing girl who goes to Kadic, but he does not know who it is exactly. According to Ulrich they stayed up the whole night chatting. Odd tells that she is really romantic and starts to tell a poem she send to him, but Jeremie finishes it and says that it was written by the author of The Little Prince.
Later that day the 8th graders are having a swimming lesson and Jim has warned Jeremie that he can not come with more excuses and he has to participate in the lesson. Jim has a speech for the class about water, and he totally confuses himself and he claims that he used to be a salvage diver. Odd does not listen and tries instead to find out who his mysterious girlfriend is.
Aelita’s visions are coming back; she is now being chased through the basement of the Hermitage by the Men in Black. She faints and falls into the pool. Jeremie jumps down after her and brings her back to the surface. Back in her room, she tells the others about the vision, but they do not think it is a big deal and that she should just rest. Odd is again chatting with his cyber-girlfriend and takes the computer with him to class. Right after Jeremie closes the door, Aelita leaves the bed.
In the science classroom Odd bumps into Sissi, claiming he mistook her for a doorpost and then he finds out his cyber-girl is in their class. Jeremie then remembers that he has not made a Superscan and when he does he finds an activated tower. He, Ulrich and Odd ask if the can go to the bathroom, but Mrs. Hertz, who is in a very bad mood, does not allow them to leave. Meanwhile Aelita returns to the Hermitage and she mixes pictures of the abandoned house, with images of the place when someone once lived there. In the living room she sees a man in a white lab coat playing a piano, which fades away rather quickly.In class, Mrs. Hertz asks Sissi a question, but she is unable to answer it because she was drawing an arrow-pierced heart on paper instead of paying attention in class. The bell rings and Jeremie goes to get Aelita, while Ulrich warns Yumi, and tells the others to meet up at the Factory. Aelita walks to the room where she found Mister Pück and is getting more dreamlike visions. When Jeremie comes to her room, he finds it empty, with Mister Pück on the pillow. He calls Aelita and they decide to meet at the factory. Then she sees the Men in Black again, and now the man in the lab coat reappears outside the door, he calls her by her name and tells her to come quickly. He shows her a secret way to the sewers.
She meets the other in the Lab and says that she had more visions and that the man she saw was… Franz Hopper. Odd then realize that the visions could be X.A.N.A.’s attack (he explains that X.A.N.A.'s implanted virus is stimulating her cerebral cortex, placing the her in an artificial sleep) and Jeremie confirms that it could be true. Odd and Ulrich are transferred first, into the desert. Then he summons the vehicles, then Aelita and Yumi are virtualised. The tower is guarded by one Tarantula and two Bloks. Yumi drops off Aelita and the warriors engage combat with the monsters. They kill the Tarantula and one Block with no problem, but Aelita runs to the edge of the sector and is taken by the Transport Orb to Carthage, to find information on the visions. Jeremie disagrees with her plan, but she does not listen. Meanwhile Yumi kills the last Block and Jeremie tells the team to go to Sector 5 and find Aelita.
When the team arrives at the Carthage the countdown is still ticking and Aelita is caught by the Scyphozoa. They find her on the other side of a big room and there is only one way to her, by jumping between moving pillars in the middle of the room. Odd fires a Laser Arrow at the Scyphozoa, which releases Aelita, but then Odd is smashed between two pillars and is devirtualised. Then Ulrich is able to chase the Scyphozoa off. Yumi presses the Key right before the countdown reaches zero. They reach the elevator and the celestial dome.
Yumi and Ulrich jumps on there vehicle, but Aelita stops at the interface to get information. Jeremie tells her that she needs to deactivate the tower, but she refuses to listen. Jeremie gets so desperate and angry that he even orders Ulrich and Yumi to “Drag her out by force!” Three Mantas appears and Yumi and Ulrich tries to fights the off. Jeremie tries to convince Aelita to leave Sector 5, but she still does not listen. The Mantas drops Flying Mines and the Scyphozoa returns and attacks Aelita. Ulrich tricks the mines to crash into the Scyphozoa forcing it to let Aelita go. Then they return to the desert and Aelita deactivates the tower.Back at school, Aelita tells the gang that her visions are gone, but she still wants to find the origin of the hallucinations and she feels like she is reliving the events that she was dreaming. Odd finally gets to meet his computer-girlfriend in real life, finds it's really Sissi, and when she sees Odd she asks why he's acting so strange, almost "as if he never saw her before". Odd whispers to himself "never like that".
- The original French name for this episode is Empreintes.
- Chronologically the events of this episode take place after Temptation, however it is aired weeks before.
- The Scyphozoa attacks Aelita twice in this episode.
- Odd's farewell clip from Echoes is taken from this episode.
- This is the second time Odd gets squashed in sector five.