The episode opens in Carthage, with Aelita collecting data at the interface while Odd, Yumi, and Ulrich fend off several Mantas. As Odd and Ulrich ride on an Overboard together, two Mantas work together to fire a strange red beam at them, which causes a delayed devirtualization. After the mission is over, Jeremie is curious about the beam, and plans to research what happened. However, when Odd reminds him they are running late to rehearsals for a school play, and the Lyoko Warriors return to campus without investigating.
In the gym (which has been converted into a makeshift theatre), Ulrich, Odd, Jeremie, and Yumi hold an open rehearsal, performing a scene from Act III of Cyrano de Bergerac. However, in the middle of the scene, Odd and Ulrich both begin to hallucinate that they are on Lyoko. When they start attacking audience members, believing them to be X.A.N.A.'s Monsters, they are restrained and rehearsals are cancelled. Believing the boys to be mentally ill, an ambulance is called, and Ulrich and Odd are taken to a hospital. Yumi and Aelita decide to go to The Hospital to monitor the boys' conditions while Jeremie returns to the Lab to follow through with investigating the strange beam.
At the hospital, Jeremie calls Yumi and confirms that the beam did in fact cause Ulrich and Odd's hallucinations, and tells her that she and Aelita must bring them back to the Factory so that Jeremie can correct the problem. Yumi distracts a nurse while Aelita enters Odd and Ulrich's room. Aelita plays into their hallucination to get them to follow her, and together they manage to outrun the hospital staff and escape into town. Meanwhile, at the Factory, Jeremie discovers Monsters attacking the Core of Lyoko.
When Yumi, Aelita, Ulrich, and Odd arrive at the Factory, they are all sent to the Ice Sector where the boys' hallucination continues; they now believe themselves to be on Earth. Yumi is sent to Carthage to defend the Core, while Aelita escorts the boys to a way tower so that Jeremie can run a program on them.
En route to the tower, Aelita, Ulrich, and Odd are confronted by a Tarantula and two Kankralats. Meanwhile, Yumi reaches Core Zone and touches the Key Mechanism. She arrives at the Celestial Dome, and then enters the chamber containing the Core. In the Ice Sector, Aelita defeats the monsters and manages to get Ulrich and Odd into the way tower, where Jeremie successfully runs the program and the boys are returned to normal.
Aelita, Ulrich, and Odd are then sent to Carthage as Yumi battles Mantas to protect the Core. The trio arrives in the Core's chamber just as Yumi is devirtualized and the Core loses it's last protective layer. However, Odd and Aelita manage to defeat the remaining monsters, saving the Core. Jeremie then manually devirtualized them and performs a Time Reversion.
Back at the rehearsal, Mr. Chardin, and drama teacher, stops the performance halfway through and asks for "more insanity". The Lyoko Warriors all laugh at the irony as the episode ends.
- The original French name for this episode is Tarentule au plafond. The French title translates to Tarantulas on the Ceiling.
- The title is notable as one of the few that are not similar in both the French and English versions of the show.
- This is the only episode in which the Hallucinogenic Beam is ever used or mentioned.
- The Holomap pictured in the title screen depicts Lyoko without the Forest or Desert Sectors, which were destroyed in the episodes Lyoko Minus One and The Pretender, respectively.
- The play performed in this episode, Cyrano de Bergerac, is a real play written by Edmond Rostand.
- Room 237, where Ulrich and Odd were hospitalized, is the same room Sissi was assigned in Contact.
|Code Lyoko: Season 3|
| Straight to Heart | Lyoko Minus One | Tidal Wave | False Lead | Aelita | The Pretender | The Secret | Temporary Insanity | Sabotage | Nobody in Particular|
Triple Trouble | Double Trouble | Final Round
|Season 1 · Season 2 · Season 3 · Season 4 · Code Lyoko Evolution|