Book 1: The Underground Castle

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[Book 1]
The Underground Castle
[Book 2]
The Nameless City
[Book 3]
The Return of the Phoenix
[Book 4]
The Army of Nothing

 This page summarises the content of the first book in the quadrilogy based on the series, whose title is "The Underground Castle". More than an opportunity for a sequel to the series, this book and its sequel are among other things destined to fill in the gaps and other questions about the series' past, notably the elements surrounding Franz Hopper's life.
Paradoxically, Code Lyoko elements we discovered on TV, like how the heroes met, are modified in flashbacks that set the pace of the book's narrative.

This is why we have decided to separate the pages on the story of the cartoon completely from the information in the four books. There is therefore no mention of these novels on the backstory and prequel pages.

Everything is exposed on this page and the three that follow it.


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Synopsis & chapters
Jeremy and his friends accidentally find themselves plunged into a virtual world named Lyoko. During their journey, the 4 friends meet Aelita, a young amnesiac elf whose past is mysteriously linked to Lyoko and its secrets...


Chapter 1: A Butterfly at the Bottom of the Sea
Chapter 2: The Empty House
Chapter 3: Erik Mc Kinsky
Chapter 4: The Underground Castle
Chapter 5: Maya's Sleep
Chapter 6: I Am Not Human
Chapter 7: John F. Bullenberg
Chapter 8: Chocolate, Books and Secret Passages
Chapter 9: Eva Skinner
Chapter 10: The Secrets of the Hermitage
Chapter 11: Eva Skinner
Chapter 12: The Mystery of the Builders
Chapter 13: Eva Skinner
Chapter 14: An Unexpected Journey
Chapter 15: Eva Skinner
Chapter 16: A Brush with the Law
Chapter 17: Something in the Mind
Chapter 18: The Secret Room
Chapter 19: Eva Skinner
Chapter 20: The First Day of School

Short summary
Several months after having killed XANA, it resurfaces on the Internet. Weakened and disoriented, it wanders for some time on the network then possesses a young American girl called Eva Skinner. Taking total control of her body, it takes a plane from San Francisco and heads to Kadic to kill the heroes while already making up enrolment papers for the Academy by hacking it through the Internet.

Far away from all of this, the heroes are confronted by an amnesia crisis: Aelita loses her memory at the same time of XANA's return. Deciding to take advantage of their final day of holidays, they set up at the Hermitage and retell their story in a video diary, with the main goal of restoring Aelita's memory in mind.

It's also an opportunity to explore a little more of the mysterious Hermitage. From discovery to discovery, the heroes find a trace of one of the individuals who helped construct the villa. Urgently taking a TGV to Provence, they talk with him and learn that Franz Hopper had him create a secret room in the Hermitage. Back in the Parisian region after many adventures, they assemble the clues that Franz left them and discover the room in question.

It contains an old video cassette that Franz left as a farewell present to his daughter.
In it, Franz explains that he was a member of a secret project in Switzerland, Carthage. He left the project with his wife Anthea when they realised that it was harmful to humanity. Following this, the men of Carthage kidnapped Anthea and badly injured Aelita's head, forcing Franz to virtualise her onto Lyoko with the consequences that we know well: the shutting down of the Supercomputer by Hopper and the death of XANA.

He leaves two missions to his daughter in the video: one is already one, it's to deactivate XANA and the Supercomputer. The second is more complex: find Anthea Schaeffer, Aelita's mother.

The next day, the heroes prepare to go back to school without knowing that Eva Skinner, possessed by XANA, will be there too.

Detailed summary
Previous elements in the action of the novel

A number of chapters and parts of chapters of book 1 of the Code Lyoko Chronicles talk about events from the animated series. In reality, they're in situ visions of a diary that the heroes are making during the action of the book (so after XANA's death) to recount their fabulous adventure. These sections of a "flasback" story are scattered throughout the action of the novel.

In doing so, the story of the 4 first seasons of Code Lyoko is summaries during only the first book and allow a reader who hasn't followed the series to still be able to read the 4 Code Lyoko Chronicles books while understanding the whole story (which was interesting for the publishers of the four books).

Nonetheless and logically, for a Lyokofan who has followed the whole cartoon, the revisited elements of the series undergo all sorts of transformations because the publisher needed to create a synthesised story. Here is the summary of the recounted elements, with the modifications in question. This summarises chapters 2, 4, 5, 6 and 17 of book 1.

While searching for machine pieces for his robots, Jeremy Belpois, 12 years old and student at Kadic Academy, discovers a secret passage that goes from the park of the school grounds to a factory not far away. The manhole cover that hides the passage, the entrance to the factory and the maze-like path through the sewers is defaced in several places with a logo featuring the name "Green Phoenix".

Nonetheless, deciding to explore this new place no matter the risk, Jeremy goes. Activating the lift out of curiosity, he descends into the dark depths and discovers a room containing a seemingly ultra-sophisticated computer terminal. Dubious, Jeremy wonders if he has discovered an abandoned film set or a military project. Recklessly he stays and explores. The terminal was inactive and not linked to any hardware worthy of being called as such, the tech whiz decides to search the site, certain there is another room.
The lift doesn't seem to take him anywhere else. He then discovers, while exploring the floor, a conduit that leads further down, concealed beneath a slab on the first floor. Removing it, it leads into a second room which only contains three large tubes connected to the computer above, but also just as inactive. Going even further, he arrives at the end of the tunnel but is stuck by a security door requiring a passcode. Only one hint is given by the device: D3L3ND4. The word consists of 7 letters but the response can have up to 8 according to the case. The brainiac finds himself stumped on this enigma.

Jeremy returns to the school. Reflecting on his relentless headache, he overhears a conversation between the principal and Paul, a friend who is visibly the head of an enigmatography club. Jeremy requests the benevolent individual's help with the enigma. He doesn't waste time in solving it: it's "leet" code, a secret code which replaces certain letters with numbers. The hint word D3L3ND4 therefore really means DELENDA. It's a Latin word meaning "that which must be destroyed". This same work is recorded in the history books thanks to a speech from a Roman senator whose words have been remembered through the ages: "Cathago delenda est" which means "Cathage must be destroyed".

Back at the factory that evening, Jeremy tries to write the word CARTHAGO in "leet" code: C4RTH4G0. The doors then open on a room containing a deactivated Supercomputer. Jeremy turns it back on. He goes back up to the terminal room. A holomap activates representing a virtual world. The screens bring Jeremy into contact with a young elf-like girl.
Jeremy, fallen for her charm, speaks with her. He then realises, stupefied, that she seems to be inside the virtual world... Since she has no memories anymore, Jeremy names her Maya. At first he thinks that she's a very evolved form of artificial intelligence. However...a Turing test and numerous discussions with her convince Jeremy of Aelita's humanity... But how the heck did she get into the video world?
Jeremy then studies the three large tubes on the lower floor. These cabin-like things have a strange inscription: "Scanner. Virtualisation chamber. Danger." Could it be the key to solving the mystery?

As he returns to the school to satisfy his obligations as a student, strange phenomenons start occurring around him. Firstly, he's electric shocked by a coffee machine at the school. Several days later during the evening, the robots he built turn against and attack him.
Both times, he's saved when one of his classmates interrupts: Ulrich Stern. Seeing him bear witness to the curious happenings surrounding Jeremy, the boy genius decides to take him to the factory the next day. After presenting him to Aelita and his hypothesis as to the scanners being the gateway to the virtual world, he asks him if he'll act as a guinea-pig. Ulrich isn't very thrilled about the idea and proposes a second option.
He decides to capture Kiwi, the crazy dog belonging to his new roommate, hidden in their room. Taking advantage of the late hours and the dog's master being asleep, he steals the dog and places him in a scanner. But Odd Della Robbia was woken by the kidnapping of his pet. He follows Ulrich to the factory and accidentally takes his dog's place in a scanner.

After Jeremy launched the virtualisation, Odd landed in Maya's virtual world, with the appearance of a virtual humanoid cat. In this world, the senses are modified, physical abilities multiplied.
What comes next escalates to phenomenal proportions. A battle breaks out in the virtual world. Digital cockroaches take after Odd, who is forced to flee. Ulrich joins him via virtualisation, in the appearance of a virtual samurai. Together, they confront the cockroaches. One with katana swinging, the other with laser arrows blazing.
At the same time, Maya is also on the run. A number of memories then come back to her. Her name is not Maya but Aelita. The person controlling the monsters is XANA, a program in the Supercomputer that detests the entire world and Aelita in particular, who is the Saviour of this virtual world named Lyoko. Finally, she remembers the numerous towers that are spread around Lyoko are access bridges to the real world. They allow XANA and Aelita to act on the electrical networks there. When XANA attacks, it enters a tower and takes control. Aelita then enters the tower in which XANA is attacking: it is radiating red signals rather than blue. Aelita enters and mechanically enters the Code Lyoko on an interface: XANA is chased from the tower and the cockroaches disappear.
Jeremy then brings Ulrich back from Lyoko. For Odd, he was already forcefully brought back to the scanner after the Kankrelats shot him with lasers and took all his virtual avatar's life points away. Unfortunately, Jeremy doesn't manage to materialise Aelita in the scanners.

He then sets to work on this thorny problem. He discovers that Aelita was indeed sent to Lyoko via thr scanners. But he can't bring her back because the data concerning her were modified after she was virtualised. She had obviously had memories added, probably those concerning her role in the virtual world. This cluster of memory was blocking the memories of her life on Earth.

Several days later, a new girl joins the adventure. Yumi Ishiyama, a year older than Odd, Ulrich and Jeremy. She discovers the factory by following Ulrich. Knowing how to fight and being able to lend her feminine ear during Aelita's time of discomfort, she is finally accepted into the group. Her first virtualisation has her end up as a sort of virtual geisha, capable of fishing with two sharp fans.
Immediately after that, XANA sends an immense virtual Tarantula. It captures Aelita and tries to drain her memory through a tube but Yumi destroys it.

Aelita is then curt, she asks Jeremy to destroy the surplus memories in order to make her rematerialisation possible. The day comes, Yumi stays on Lyoko to reassure Aelita. Jeremy does as he's told and the rematerialisation works: Aelita exits the scanners with red hair and completely out-of-date fashion. Ulrich and Odd welcome her to Earth and bring her up to the computer room where she jumps into Jeremy's arms.

Unfortunately, when the heroes think they'll be able to shut the Supercomputer down and deactivate XANA, the unthinkable occurs: the extinction of the machine makes Aelita lose consciousness. Jeremy realises that the link between XANA and the young girl renders turning the machine off impossible.
Jeremy can't find a solution to this problem. That's when the answer came to him one day as he was sitting alone in front of his computer screen. Franz Hopper, Aelita's father and the creator of Lyoko, presented himself to him. Communicating with Jeremy, he asked him to head to the factory to "destroy XANA!" Not wasting a second, the 4 kids guided by Jeremy headed to the factory and plunged into Lyoko. At the edge of the Ice Sector, hidden behind a waterfall, they find the entrance to Sector 5: the Core of Lyoko which takes the appearance of a vast digital city composed of blue blocks. Franz was waiting for them in the form of a luminescent sphere. He then explained his plan to Aelita, they had to go to the Fifth Sector to launch a program which would annihilate XANA.

The situation then started to spiral out of control:
Yumi was devirtualised by XANA's monsters. Back on Earth, she stumbled upon a disaster scene in the computer room: William Dunbar attacked Jeremy, under XANA's control. The girl lead him into the factory to fight him away from Jeremy.
On Lyoko, on one side XANA sent its most powerful monster: a colossus several metres in height that Ulrich decides to confront.
On their end, Odd, Aelita and Hopper go into Sector 5 and install the program to kill XANA on the Supercomputer.

Odd is devirtualised by the hundreds of flying mantas guarding Sector 5. Back on Earth, he saves Yumi just in time by catching her after William throws her off the second floor of the factory. Ulrich holds the colossus back valiantly but ends up being squashed.

Hopper then explains to Aelita several things: her mother disappeared and he doesn't know where she is but he left something that will help find her in an old, hidden room in their old house.
As for the XANA annihilation program, it requires energy to be launched from the Supercomputer... And this energy is none other than Franz Hopper himself, in virtual form. It's then that Aelita assists, in despair, with the disappearance of her father, who is sucked away by the Supecomputer and disappears forever... From there, the program launches and XANA is removed from the virtual world while on Earth William Dunbar is freed from its grip and falls unconscious.
XANA is dead and the fight is over.

The novel's story

Tuesday the 21st of December, between the United States and Japan, the undersea cable that transmits the Internet exchanges between the two countries is malfunctioning...and before the repair robot even grazes the surface, it's back in working order with an unusual crackling noise...

At the same moment, at Kadic Academy, Aelita, Jeremy and Odd are talking about the upcoming holidays and about the "diabolical plan" they'd concocted. Right in the middle of the discussion, Aelita suddenly loses her memory and no longer recognises her friends... (Chapter 1)

The friends meet up on the 9th of January. Their diabolical plan has been put in motion: Jeremy had simply told the 5 friends of the group to meet up a day before class started at the old abandoned villa called the Hermitage, the old residence of Aelita and her father. To do this, each teen had told their parents they'd be staying over at someone else's house.
The group then found themselves reunited: Aelita and Jeremy spent the holidays together and she started to recover her memory...partially. She still didn't have any trace of a memory of XANA or Lyoko.
While the mood is warm in the Hermitage with meals cooked by Odd and Jeremy, followed by a snowball fight in the garden, Jeremy reminds them of their reason for being at the Hermitage: investigating its mysteries. On that note, Jeremy takes out a digital camera and with his friends, they start to recount their secret adventure as Lyoko Warriors in a kind of diary. They especially hope that this will help Aelita to recover her memory. Ulrich firstly recounts their unusual encounter with Jeremy (Chapter 2).

At that same moment, elsewhere, a young American fan of the Ceb Digitals group and their singer Gardenia receives an email from a supposed member of a forum. The email seemingly contains a photo of the artist from the band. When he opens it, he realises that it's just a fake...
The only image that opens on the boy's computer is a logo. A very familiar eye... In the young man's computer, rummaging about, XANA prowls...brought back to life and without searches for its own memories throughout the Web. (Chapter 3) While Jeremy recounts the entirety of his exploration of the factory, his discovery of the Supercomputer and his meeting Aelita, whom he originally named Maya (Chapter 4), the program enters a large music site from which the owner can't chase it out, then leaves and passes through the mobile phone network...still searching for the memories it no longer has (Chapter 7).

Interrupting their diary for a moment, the heroes escape the cold in the Hermitage. Yumi showers to get warm while Odd and Ulrich watch a horror film. Jeremy and Aelita talk about Lyoko and XANA in the kitchen, while preparing hot chocolate. Following her friends' story, some memories from her virtual life came back to her. After Odd kindly slipped some peppers into Ulrich's hot chocolate, Yumi proposes they explore the Hermitage's attic. While they return to the mess in search of a clue, Aelita asks why the Hermitage was abandoned. The students then tell their amnesiac friend the start of the story, which they hadn't already addressed. They remind Aelita that her father was Franz Hopper, a very smart man who created the Supercomputer and Lyoko. They also tell her that before she was virtualised, she was already a student at Kadic Academy...but everything changed for an unknown reason on June 6 1994 when her father fled with and virtualised her urgently. Aelita then asks about any news about her mother...but on this too, the heroes have absolutely no information (Chapter 8).

Odd then proposes a game of hide-and-seek to loosen the atmosphere. Jeremy takes advantage of it to take Aelita down to the Hermitage's basement and find out a little more about her father. He reveals to her that the old villa possesses a number of secret passages, a number of which are still unexplored and some of which lead to the factory. No complete plan of the house seems to have been left by the people who came after Hopper fled. Aelita then realises that the Hermitage must have been built by someone. And that's when at the back of a dead end, she and Jeremy find a sack of cement labelled with the proprietor: "Broulet and Brothers", a masonry company at 117 Rue de the other side of the city.
Outside, Ulrich and Yumi are looking for a place to hide in the garden. When William, another boy in from their school passes not far from the Hermitage, Ulrich tackles Yumi to the ground so they won't be seen. Taking his reaction as one of jealousy, Yumi becomes angry and scolds Ulrich, who is left speechless (Chapter 10).

Meanwhile in the United States, Eva Skinner, a young, trendy girl who's president of the Ceb Digital's local fan club is preparing to help out at one of their concerts at her school. When she touches her computer, the eye of XANA appears on it and a spark jumps from the mouse, remaining in her all the way until the concert and the moment when she begins to feel ill. Waking up at a hospital. Eva Skinner's body fights weakly for a moment against XANA's grip, which had taken over the body. Eva ends up being completely overwhelmed. XANA, strong with a newly-acquired body, escapes the hospital through a window and steals the clothing of a passer-by before going by its new identity: Eva Skinner. Collected by a police officer, she asks directions how to get to France. Once informed, she gets rid of the officer, takes his car and departs for San Francisco airport (Chapters 9, 11, 13 and 15).

In France, leaving Ulrich and Yumi at the Hermitage to reconcile in Aelita's company, Odd and Jeremy go to the address they discovered. Invited to have tea with the owner of the building, they learn that the Broulet brothers' company is no more. After the death of two of the three brothers following a scaffolding accident, the final brother sold shop and moved out. The visit is nevertheless a success: the two heroes return with the phone number of the third Broulet brother (Chapter 12).
Back at the Hermitage, Jeremy calls the man. The tentative call from Jeremy turns up short: the moment the boy mentions the name Hopper, his contact declares he knows nothing and hangs up. After a short debate, the heroes then decide to go to Provence, straight to their contact's house, because one thing is obvious: he knows something. Jeremy reserves train tickets by hacking Kadic's accounts and paying with the principal's credit card. Go there in the afternoon, return that night.

Quickly disembarking from the TGV at Marseille-Saint-Charles station, the heroes arrive at the house of Broulet's son and his wife. After some negotiation, they end up talking to Philippe Broulet.
After some long hesitation, the man comes to the table and reveals to them why he didn't want to talk to them about that time in his life. At that time, a mysterious individual contacted him and asked him and his brothers to do a large amount of work on an abandoned factory. Philippe Broulet understood that the work was probably a government secret: they were driven to the site blindfolded, the group that sent them payments via bank deposits didn't exist: it was a shell company. But the colossal amounts of money they were paying encouraged them not to ask any questions.
Later, the same mysterious man accompanied by Franz Hopper had them build the Hermitage under the same circumstances. In the end, the final episode of the story occurred when Franz Hopper, exhausted and visibly worn by his work, asked him for a final service: build a room in the Hermitage and make it completely concealed from the outside. During this period, Franz was no longer accompanied by the mysterious individual. He was nervous and very stressed. He paid Broulet generously, though much less than previous times.
The final story won the heroes' attention: Franz walled this room up to protect it. He had to deal with the fact that it could appear on a plan of the house and he had left a map that "only the right person can find."

Leaving the Broulet house, the heroes rush to the train a little before 11 o'clock to have the time to check the Hermitage the next day to search for this mysterious room...before school comes back. In their hurry they take the train before the one they booked without having changed their ticket (Chapter 14).

The troubled then begin for our heroes. They come across a psycho and slightly schizophrenic transit officer. He, not content with just checking their tickets, questions how they were able to pay: the principal's credit card. Not believing the heroes' lies for a second, the officer refuses to allow the unaccompanied minors to stay on the train and hands them over to a police officer at Lyon.
Agent Crane is luckily far more understanding than the transit officer. The heroes admit their mistake in hacking the principal's credit card. When Aelita tells him why they made they voyage: to find information on her deceased father, the agent is touched and accepts to not alert their parents. He let them off with a warning and forces them to reimburse the principal's account electronically, then arranging with his brother to take the kids back to Paris on a truck in the night. The voyage is uncomfortable but our heroes are saved from a good scolding from their parents.

Back in the Parisian region, the heroes get to the Hermitage.
Reflecting intensely, Aelita ends up finding the message her father left for her. It was hidden in invisible ink in a seemingly empty notepad Aelita found at the Hermitage. To reveal the ink, they needed to use a chemical ingredient contained in a chemistry set, hidden in the attic. Hopper betted on his daughter's passion for chemistry to hide the message where only she could find it.
Thanks to the instructions in the notebook, the heroes find the secret room in the Hermitage. Hopper left an old video cassette there, and what a show it was. It contained old family photos of Aelita, notably photos of her mother Anthea!

In the recording, Franz then explained why things happened! Franz Hopper's real name was Waldo Schaeffer. He and Anthea worked together for a long time on a revolutionary project in Switzerland. Project Carthage. Realising that the project wasn't destined to save humanity but was a risk, a road to ruin, they left the project. Anthea was captured at that time. Franz then built his Supercomputer and Lyoko and used the same programs they developed for Carthage. The goal was to protect people from Carthage himself.
Things then went bad when the men of the project found Hopper. In the escape, Aelita was gravely injured in the head. Hopper had no choice but to virtualise her to save her, despite the danger XANA represented.

Hopper leaves his daughter two missions at the end of the video. For one, shut the Supercomputer and XANA down so humanity can never use them for evil means. Then, find Anthea, who is still alive but in the hands of Project Carthage. Unfortunately, a some interference cuts off some of the goals he sets in the video, and the cassette doesn't reveal the end of the message because of its obsolescence (Chapter 19).

The next day, the 10th of January, the heroes arrive at Kadic for their first day back at school...ready to begin once again their double lives and go on the search for Anthea (Chapter 20).
At the same moment, Eva Skinner takes the plane from San Francisco to France. Hacking the Kadic files, she was already enrolled as a new student and had time to reflect on her plan to approach the heroes, develop a friendship with them...then eliminate them... (Chapter 19)