About the characters

- Yumi is the second character to be attacked by the Scyphozoa!
- Ulrich and Yumi argue because he, seeing Yumi arriving late, assumed she was with William.
- Mr Ishiyama’s first name is Takeho and is from Tokyo, coming from an underdeveloped area of lower Japan.
- Odd believes he’s a great actor, he knows that an unjustified absence will result in suspension, he finds it strange that Sissi was so helpful, and finds that being crushed by a pillar in Sector 5 is like being run over by a steamroller.
- Sissi accepts to be punished on Yumi’s behalf and asks nothing in return.

About errors

- Yumi’s outfit is reversed during one shot in the Celestial Dome.
- The door to Sissi’s room opens towards the hallway instead of the inside when she comes out.
- The colours of Odd’s pants are inversed when Ulrich asks Sissi if she has time to listen.
- The factory microphone is in Jeremy’s right ear when he turns to see Yumi coming in late.
- When Jeremy decides to abort the mission because of the Scyphozoa, he says “Why would they go after you?” when he should’ve asked why would “it” go after Yumi.
- Odd’s undershirt is missing from his torso when he takes the dress from Ulrich outside Yumi’s house.
- The countdown timer keeps changing from the standard digital clock font to a more rounded one.

About the series

- French title: Chaînon manquant

- First appearance of the GameBoy game Tutur 2000! Odd plays it.
- First of two episodes in which the Scyphozoa attacks someone other than Aelita (Yumi)!

About references

- Mr Ishiyama: “I’ll have another shiro-an. You did a very good job on the white bean paste!”
Shiro-an beans are a key ingredient in white bean paste, a sweet bean paste of Asian origin. White bean paste is commonly used in sweet dishes such as pastry.

- When Yumi’s mother talks about her husband as a city man, she makes an allusion to the immense megapolis that extends the east coast of the archipelago. It’s present between two landmarks: the cities of Fukota and Tokyo. Mr Ishiyama therefore lived in one of these ultra-urbanised zones, Kanto housing more than three quarters of the Japanese population in a small area. Ms Ishiyama prefers the regions of the Japanese west coast, almost desert-like.

- When Ulrich walks on tiptoe in Yumi’s house, he steps on a console inspired by the GameBoy Color.

- The episode title comes from two things: one is the fragment XANA stole from Yumi, the other is more scientific…
It’s a missing step in the evolutionary process of human beings; a stage which did indeed occur but we cannot find historical proof of: the missing link of our evolution.