Laura and Jeremie complete their virus. Laura is keen to implement it, now understanding what a dangerous threat X.A.N.A. is, but Jeremie insists that they wait until Anthea is finally found. Laura, however, has other ideas.
Unfortunately, William is being mistreated by the others again. Laura approaches him and asks if he would like to come with her and plant the virus, asking whether he wants all of this to be over. William is hesitant, saying he's a part of the group and they're best and close friends now.
When he offered a book of poetry to Yumi, he is turned down as she has a math test to study for. Laura comes back and asks if they really are his best friends. She compares herself to him, saying that they are alike in many ways, both easily misunderstood. William reluctantly agrees to the unauthorized mission.
Laura gets William to the Cortex without much trouble, guiding him as he pilots the Skid. But when he gets to the Cortex, Laura has some difficulty programming the MegaPod. Dozens of Krabs appear and William gets panicky, pushing Laura to work faster. He changes his mind a moment later: the Scyphozoa appears. He yells at Laura to devirtualize him immediately, but she gets confused as to what he's really after - the Megapod or devirtualization - and doesn't understand why they should abort the mission. William desperately attempts to use his own weapon to devirtualize himself - but it is destroyed by the Krabs shortly after he picks it up. The Scyphozoa ensnares William and is ready to possess him again.
Yumi enters the lab, wondering where William was because he hadn't turned up to an obstacle course in gym class, which would've been a good opportunity to show off, and it was strange for him to skip it. She questions Laura until she notices that William's virtual icon has became black. She becomes furious, giving Laura a short lecture on how William was possessed by X.A.N.A. for a long time before she arrived (Last episode in Season 3 and in Season 4 all the way to episode 93). Laura simply states that she didn't know. Yumi calls the others in and she goes into the Cortex with Ulrich and Aelita to rescue William. Jeremie furiously scolds and rebukes Laura, angry about what she tried to do without consulting him first.
On the Cortex, the Scyphozoa has not managed a full possession. William is being held up above the ground by its tentacles, surrounded by a black aura. He raises his hand and a digital sound comes from his mouth, commanding the Krabs. The three Lyoko Warriors can't do anything against the massive army of monsters, and they take shelter behind the Megapod. They decide that talking to William and trying to wake him up is the best course of action, acting as a distraction so someone else can get closer to the Scyphozoa and sever the mental connection between it and William.
Ulrich fights William, constantly goading him to try and remind him of their romantic rivalry and his life on Earth. William slowly becomes more and more human-like again, eventually allowing the Scyphozoa to be cut off. His black aura disappears and William returns to normal, thanking the others for saving him. This is when Odd arrives ready to kick some monster butt, only to be very disappointed at the empty landscape.
A furious Jeremy finally puts his foot down! Laura has definitely gone way too far this time! He tells her that he is going to launch a special return to the past and fully erase her memory. Laura doesn't seem worried about it, saying the program won't work on her since she had altered it. But Jeremie states that by making a version making it focus on her, he can in fact erase all of her memories of the Factory, the lab, Lyoko, and even X.A.N.A. Laura smugly says that such a reversal of time has no effect on her. Jeremie contradicts her, stating that he had modified its function, that he can wipe her memory entirely and does so.
- The original French title for this episode is Mutinerie.
- The Catalan subtitles for this episode can be found here: Mutiny: Catalan Subtitles
- Laura is no longer a member of Team Lyoko due to her betrayal and defiance.
- Second time a Lyoko Warrior was kicked out for betrayal (the first being Sissi).
- The title refers to Laura defying Jeremie and the rest of the gang and acting out on her own.
- First time we see Yumi's gym clothes in live action.
- This is the first and only time the Scyphozoa has ever appears in Code Lyoko Evolution.
- First and only time the Scyphozoa was destroyed in this season (or overall).
- William was back under X.A.N.A.'s control, however, it was only for a few minutes.
- Last time the Time Reversion launched by Team Lyoko in Code Lyoko Evolution.