Franz Hopper contacts Jérémie to give him some research on making an anti-XANA program, while Aelita has a premonition nightmare of Hopper dying.
This episode contains examples of:
- The Atoner: Subverted with William. He attempts to be this, but is rejected by the Lyoko Warriors. The best help he ended up providing was to distract Sissi when she's trying to uncover their secret.
- Break the Cutie: Aelita's left heartbroken at her father's death and breaks down into tears as she returns to Earth. Odd, who is normally the comedic one, begins crying as well as he sees Aelita totally grief-stricken. The last scene is of Ulrich, Yumi and Odd solemnly watching Aelita sob in Jérémie's arms; grieving the loss of Franz Hopper.
- Dreaming of Things to Come: Aelita dreams of her father's Heroic Sacrifice and is terrified at the thought of losing her father; the only true piece of her past that she truly cares about.
- Dying Moment of Awesome: Downplayed, as he doesn't actually die, but Ulrich is able to destroy the Kolossus before being devirtualized when the Kolossus body smashes on top of him.
- He Who Must Not Be Seen: Averted with XANA in the end of the episode. When XANA is being destroyed, he is forced out of William's body in the form of a giant spectre with a humanoid appearance and with the eye of XANA on his chest. Then he takes the form of a screaming humanoid face, and then the form of the eye of XANA before he disintegrates, being totally destroyed. Yumi and Ulrich witness the whole thing in shock.
- Heel–Face Door-Slam: William is faced with this reaction from the rest of the group after being freed.
- Heroic Sacrifice: Franz Hopper sacrifices his own life to provide Aelita and Jérémie enough power to run the multi-agent program.
- Killed Off for Real: The case with Franz Hopper. As the other times he was able to simply use one portion of his energy to save Team Lyoko, this time he uses his entire being to power Jérémie's multi-agent program and allows himself to die in order to see XANA destroyed and the world safe.
- Little "No": Aelita says this when she has to make a choice between saving her father or destroying XANA.
- Nice Job Breaking It, Hero: Yumi refuses to let William be virtualized on Lyoko again because she thinks XANA might seize the opportunity to control him again, but by doing so, she allows XANA to take control of him, but on Earth.
- No Holds Barred Beat Down: Yumi is given one by a Xanafied William and, when coming to her rescue, Ulrich is given one as well as he's tossed around the room like a ragdoll.
- Punched Across the Room: Xanafied William does this to Yumi and Ulrich.
- O.O.C. Is Serious Business: As a distraught Aelita cries in Jeremie's arms as she mourns her fallen father, Odd watches and silently begins to cry as well. The one time in the series we see him break down in actual tears.
- Pyrrhic Victory: XANA is finally destroyed... but at the cost of Franz Hopper's life.
- Sadistic Choice: As Franz gives his remainder of life to boost Jeremie's multi-agent program to finally destroy XANA, Aelita must choose between saving her father or killing XANA. She reluctantly chooses to destroy XANA as Jeremie points out that her father will have died for nothing unless she acts now to make sure he doesn't die in vain.
- Shower of Angst: Aelita at the start of the episode, especially since she has a premonition of her father dying.
- What the Hell, Hero?: Aelita calls out Yumi, Ulrich and Odd for their treatment of William, pointing out that she herself had been controlled by XANA several times, and that any one of them could have ended up under XANA's control.
- Yank the Dog's Chain: William. While reluctant, the Lyoko Warriors agree to let him stick around to serve as backup in case he is needed, however just as Jérémie made the choice to send him in, he ends up being xanafied once more, becoming a hindrance to their goals one last time, and preventing him from settling the score with XANA.
