|Air Date (US)||December 9th, 2005|
|Air Date (France)||February 8th, 2006|
|Written by|| Bruno Regeste|
|Storyboard by|| Paul Beneteau|
Alaikin le Dong
|Followed by||The Key|
The episode begins in Carthage as Team Lyoko is fending off a group of Mantas. While Aelita is using the computer interface, a Manta swoops down to attack Ulrich, who dives and slices the belly of the Manta with his katana. The injured Manta comes back for another pass. This time, Odd bends over and gets a clean shot at the Manta's Eye, destroying it. A streak of laser fire signals the arrival of another three Mantas. Aelita finishes her work and uploads the data to Jeremie, who brings up their vehicles. Jeremie opens up one of the data tunnels, allowing the team to leave.
Moments later, everyone crowds around Jeremie to see the results of the mission. Jeremie tells them that he can decrypt Franz Hopper's diary with the retrieved data. Aelita brings up the fact that they will need the processing power of the Supercomputer to run the decryption program, which means they will need to activate a tower. Everyone, except Jeremie, then goes out to get lunch. In the Cafeteria, Odd tells Rosa that Jeremie's letting him have his meal. She then heaps on another helping of mashed potatoes, commenting that Odd shouldn't be so scrawny, seeing as he has such a large appetite. Odd responds, "I'm not scrawny! I'm svelte." Odd, Aelita, and Ulrich sit down at a table, where they discuss their grade point averages. Incredibly, Odd, with a 75 GPA, has a higher score than Ulrich, with a 73, despite the fact he stinks at school. When they ask Aelita, she answers, saying 95.2, leaving the boys shocked. Aelita tries to act as if it isn't a big deal, saying it was only because of math scores. When Ulrich accidentally mentions that Aelita isn't human, she just says that she knows she isn't human. Aelita mentions that she sometimes gets deja vu, feeling as if she has already lived on Earth. Minutes later, after lunchtime, they are outside when Odd's cell phone begins to vibrate. He takes it out of his pocket and sees that it's a text message. Odd tells his friends that a mystery girl wants to meet him in the woods. He then starts walking into the woods. At the Factory, Jeremie detects an activated tower while working on prepping the decryption program. He calls Aelita and Ulrich, telling them to inform Yumi and Odd and to get to the Factory. Aelita then starts to call Yumi while Ulrich text-messages Odd. In the woods, Odd is searching for the "mystery girl" when his phone gets a message from Ulrich: S.O.S. X.A.N.A.. Immediately afterwards, one of X.A.N.A.'s spectres invisibly begins to sneak up on Odd. He turns around and screams.
Yumi, Ulrich, and Aelita step into the Lab. Jeremie asks where Odd is, getting a response of, "He was supposed to be meeting some kind of mystery girl." As the three head down to the Scanner Room, Jeremie tries to call Odd. The call reaches the intended phone, but Odd's phone is laid on the ground in the woods, with no one picking up. Giving up on finding Odd, Jeremie begins the virtualization process on the other three. They appear in Lyoko's Mountain sector, forming a triangle. Odd steps into the Scanner Room, irritatedly telling Jeremie that he was "busy". During Odd's virtualization, Jeremie detects a bug. Moments later, a window pops up on Jeremie's computer screen, showing that the activated tower shut down on its own. Ulrich comments on Odd's seemingly bad mood, but Aelita dismisses it as a result of getting rejected by the "mystery girl". Jeremie then brings up their vehicles, telling them to head to a designated tower. Minutes later, they arrive at the same tower activated in the episode A Bad Turn. While Odd, Ulrich, and Yumi wait outside, Aelita enters the tower and floats up to the interface. Jeremie then activates the tower, giving it a green aura. Immediately, the decryption program activates and begins decoding Franz Hopper's diary. However, it will take a while.
Jeremie's computer spots three monsters heading towards Team Lyoko's position, but with the sudden fog there, they can't confirm. Moments later, they see three Tarantulas emerge from the fog and raise their weapons. Instead of firing at the Tarantulas, Odd fires at Yumi and devirtualizes her. Ulrich exclaims that X.A.N.A. has taken over Odd. Odd then proceeds to fire at him, firing his Laser Arrow at rapid speed. Being fired at by Odd in front and by the Tarantulas behind him, Ulrich jumps onto the Overbike and takes off. Meanwhile, at the Hermitage, the real Odd wakes up, trapped inside a water drain, which is bolted shut on top. Above him, a garden hose is spewing water inside. If Odd doesn't get out soon, he will float up to the metal gate above him, where the rising water will drown him. He then starts to try climbing up the walls, but fails.
On Lyoko, X.A.N.A.-Odd is following Ulrich, firing at him from atop the Overboard. Yumi comes up from the Scanner Room and Jeremie realizes that the Odd on Lyoko is a Polymorphic Clone. At the Hermitage, Odd loses his grip and falls back down to the bottom, where the water is rising. Desperate, he begins to shout out for help, but no one is nearby. In the Lab, Jeremie tells Ulrich to get back to the tower because the clone is drawing him away. His computer screen then shows that X.A.N.A. is trying to take control of Jeremie's activated tower. He tells Aelita is stop the decoding process and get back to Earth. Jeremie also localizes Odd's cell phone in the northeast corner of the woods, giving Yumi a general area to look for him. In the tower, Aelita can't stop the decryption program. If X.A.N.A. gets control of the tower now, he can delete Franz Hopper's diary, Team Lyoko's weapons, transfer codes, and Aelita's materialization program. He tells Ulrich to return to the tower and to isolate it from the rest of the network by cutting the cables. Ulrich flies back to the tower, which is being guarded by the three Tarantulas. He rams one with the Overbike and destroys another, but as he's about to cut the cables, the polymorphic clone interrupts him. Ulrich tells it, "You're wasting your time, X.A.N.A.. Odd has never beaten me yet." The polymorphic clone then glows a bright orange and transforms into Ulrich, except for the gray and orange color scheme. The two then run at each other and clash with their katanas.
At the Hermitage, Odd's feet can no longer touch the ground, due to the rising water. In the woods, Yumi is still searching for Odd. She calls his number on her cell phone and hears a phone ring. She follows the sound, but only finds his phone. On Lyoko, the two Ulrichs sprint away from the tower and continue to fight. Although it seems they are evenly matched, the fight quickly degenerates into a losing one for the real Ulrich, as his katana gets knocked away by the clone. While walking around, Yumi sees the Hermitage and decides to look there. Meanwhile, on Lyoko, Ulrich is getting knocked around by the clone, but he manages to grab its katana and stabs it though the heart. Ulrich then races back to the tower to cut the cables, but he is devirtualized by the last Tarantula.
At the Hermitage, Yumi hears Odd's cries for help. She stops the water flow of the water faucet, but the water has already submerged Odd. She then starts pulling on the metal lid, even though it seems hopeless. On Lyoko, the tower now glows red, being controlled by X.A.N.A.. Just as it seems X.A.N.A. has gotten hold of Jeremie's data, the tower starts glowing white, meaning its controlled by Franz Hopper. The decoding program speeds up before Jeremie's eyes. At the Hermitage, Odd is drowning. With all her strength, Yumi loosens the bolts and pulls out the lid, freeing Odd. Even though faced with death, Odd still manages to crack a joke: "No girl's ever kept me waiting that long."
The tower on Lyoko stops glowing white and becomes the normal blue. Later that day, everyone is in Jeremie's dorm room. Jeremie tells them that the diary contained a record of everything that happened during the creation of Lyoko. He also added that Franz Hopper had a daughter who was virtualized with him into Lyoko. Aelita points out that if Franz Hopper's daughter stayed on Lyoko, she would have known about it. It takes a moment for the revelation to sink in for her; She is Franz Hopper's daughter.
- The original French name for this episode is Révélation.
- This episode aired as a double bill along with The Key.
- First time Ulrich has a clone of himself on Lyoko he didn't create.
- First time Ulrich's double wields sabers.
- First shown with a green tower during the title sequence.