About the characters

- Second episode in which Yumi takes care of the virtualisation.
- Ulrich accepts to go out with Sissi for two weeks after she helps Yumi get out of the principal’s office.

About errors

- The door to Jeremy’s room often changes colour (grey, brown and blue).
- Jim’s t-shirt is blue instead of white at the moment when he sees Yumi running towards Jeremy’s room.
- When she writes on the board, it’s not the sleeve of Ms Meyer that we see but Ms Hertz’.
- The Way Tower in the Mountain Sector is activated while in this episode, XANA didn’t launch an attack!
- The enter key on the factory computer keyboard has an arrow on it just before Yumi virtualises Ulrich, while it doesn’t have one normally.
- When Yumi virtualises Jeremy, it shows him in the scanner room rather than the scanner itself.
- After Ulrich destroys the two Bloks, Aelita enters the tower but it’s not the same one. The first tower was inside a canyon.
- During Ms Hertz’ class we can see Mohamed Kantaoui of year 7 and Anouche Bedoyan and Ninon Costes of year 6.
- Odd’s pants are entirely the darker shade of purple at the moment when Ulrich asks Aelita if there’s a way to recover the memory from another tower or computer.
- Odd’s undershirt also disappears from his midriff in the scene mentioned above, as well as when Ulrich and Yumi return to the lab, and when Jeremy comes out of the scanner.
- Aelita’s outfit is reversed when she meets Jeremy.
- At the moment when Yumi’s phone rings there’s a row of students in front of her that wasn’t there before and there are students from various classes.
- The factory microphone is in Yumi’s right ear when Ulrich tells her that only Jeremy can operate the computer without making a mistake and when Odd tells her not to worry.
- In the shot following the one where we see Odd sleeping, a book appears on his table when there wasn’t one before. When the whole class sees Odd sleeping, Yumi is in the background behind Jeremy even though she’s in the year above, as well as Julie Vigouroux of year 6 and two unknown students. The students change places often during the class.

About the series

- French title: Frontière

- First episode in which XANA doesn’t launch an attack, and in which an RTTP isn’t launched! Also Jeremy’s first transfer, though it didn’t work…

About references

- The position Jeremy and Aelita are in when they touch resembles the famous painting “The Creation of Adam” by Michelangelo.

- Odd has a GameBoy whose design is the same as the GameBoy Advance SP. The game he’s playing is the famous Tetris.