Aelita jumped down. She had activated the key just in time.

"It's okay, William. Come over here!" she shouted. William destroyed the Creeper in front of him and said, "Wait! Just one or two more, okay? This is too cool!"
Then the recruit ran to destroy to last Creepers. A giant wall appeared between the two Lyoko Warriors.
"William!" Aelita exclaimed, but it was no use; they had been separated. "No!"
"Aelita! What's going on? Where are Ulrich, Odd and Yumi?" asked Jeremy who had just arrived at the lab.
"How would I know? They aren't in the computer lab?" Aelita asked.
"No," Jeremy answered. A monster appeared on the map of the supercomputer.
"Hey, Jeremy? There's a very weird-looking creature that just showed up," William said, backing a bit away from the monster that had appeared in front of him. "Looks like some kind of… uh… giant jellyfish?"
"What?" Jeremy exclaimed. "Aelita, you have to get to William! Hurry, you have to go around the outside!"

Aelita left immediately with Jeremy guiding her to where William was while the new Lyoko Warrior faced off the Scyphozoa.
"William, get out of there! Hurry up! William, do you hear me?" Jeremy told William.
"I'm not afraid of some dumb jellyfish!" William noted, raising his sword. It was so heavy that he had to struggle against its weight and momentum in order to keep it under his control.
"William, just do what I say. I don't know what the Scyphozoa wants with you, but it can't be good!" Jeremy told. The Scyphozoa lifted its tentacles and whacked William's sword away from him. It flew some distance away.
"Rats!" William said, frustrated that he had just lost his weapon like that. The Scyphozoa came closer and William backed away from it. He had to get his sword back.
"William, get out of there right now! William, do you read me?" Jeremy said. Aelita was close now, but so was the Scyphozoa. William got to his sword and took it to his hands, checking if it had been damaged.
"Relax! The Scyphozoa hasn't moved an inch. It must be scared of – whoa!" William said, though his bold words broke off to an exclamation as he saw the Scyphozoa attack him with its tentacles.

Suddenly something bright flew past his face and cut those tentacles right before they got him. The Scyphozoa looked at its severed tentacles and left.
"William? William, answer me! What's going on?" Jeremy shouted.
"The Scyphozoa almost got me. But… but something just… cut its tentacles," William said, bewildered by the close shave.
"That something was my sword," said a female voice, low and calm. William knew immediately that it was not Aelita (She doesn't have a sword, right?) so he turned to see the talker. He saw a girl with mint green hair which reached a bit past neck. That girl had a dark turquoise cape, black trousers with dark green belt and black and very dark purple shirt and. She had bright green half-gloves and dark green vambraces. Her blue eyes embodied grief, yet they had anger burning in them. Anger which was kept inside only to be unleashed. Unleashed right at him, William suddenly knew. He couldn't say a thing. It cannot be her! he thought.
"Aelita?" Jeremy asked.
"I'm almost there!" Aelita told.
"There's someone else there. It seems that she just saved William from the Scyphozoa," Jeremy told.
"What?" Aelita asked.

The girl walked over the room and took her sword from the wall it had stuck into. She then put it into the sheath on her back under the cape.
"Cass? Is that… is that you? For real?" William managed to ask, not believing his eyes. It couldn't be her, it just couldn't, he thought. The girl walked nearer to him and asked, "Well, what do you think? Is it me for real or not?"
"Cass… You… you saved me, right?" William asked.
"Indeed," Cass answered, keeping the calm tone in her voice before she let her anger burst out. "You blasted idiot!"
"Wh-what?" William asked, surprised by the sudden change.
"You moron just decided to not give a light on what your experienced comrades tell you on your first mission here, huh? Did you leave your brains on Earth or what?" Cass kept on. "Honestly, what were you thinking?"
"That… that's not fair," William tried to counter the harsh verbal rampage which, however, had already beaten him.
"Perhaps, but as you know, or at least should know, I don't appreciate those who don't use their brains. We have them for a reason!" Cass told angrily. William did not even try to defend his pride anymore. He knew that at this point he could not stop the girl from lashing out at him.

Aelita got there and looked at the situation. The girl with mint green hair was yelling at William, who seemed a little bit mortified by the situation. The girl did not seem to be a threat so Aelita approached them carefully but quite normally.

The girl, Cass, finished with her words and turned her back to William and looked at Aelita.
"Who are you?" Aelita asked her.
"The name's Cassandra," the girl told bluntly. Aelita stole a look at William. The boy looked saddened by the treatment he had just gotten from the girl.
"Make a haste, will you? The monsters are attacking the Core of Lyoko!" Jeremy told.
"Okay. Let's go, William," Aelita said. William nodded and leaned his sword on his shoulder. They left with Cassandra following them.
"I suppose you don't mind if I lend you guys a hand with this matter," Cassandra said without waiting for any reply.

They got to the elevator. It went past them just when they arrived.
"The elevator doesn't stop here, so we have to jump on it when it comes," Aelita explained to William.
"Ok," William answered. He took a look at the place.
"When I say 'now', we jump. Okay?" Aelita said.
"Sure," William said. Cassandra's words about him not caring about the words of other Lyoko Warriors bugged him.
"Now!" Aelita said and all three of them jumped. They landed on the elevator which kept going up.
"Whoa! So cool!" William said, letting excitement sweep over Cassandra's words.

The elevator stopped and a new passageway opened up.
"Welcome to the Celestial Dome!" Jeremy told.
"Celestial Dome?" William asked.
"X.A.N.A.'s interface is here. We've gotten vital information from there," Aelita explained.
"X.A.N.A.'s interface?" William repeated, surprised.
"Sector 5, also known as Carthage, is the home of X.A.N.A.," Cassandra told.
"I'll materialize Overwing to you, Aelita and William. But Cassandra…" Jeremy begun.
"I have my own way of transportation. Vert, come over here, will you?" Cassandra cut off, calling out to the distance. A cry of a Manta was heard.
"Mantas?" Aelita asked.
"Just one," Jeremy told.
"It's mine and not going to hurt you," Cassandra explained. The Manta came to their sights and Aelita noted to her surprise that this Manta was green. The Overwing materialized and Aelita hopped on it.
"Come, William!" she told the rookie Lyoko Warrior. William hopped on the Overwing too and Cassandra jumped on the Manta she had called and sat down.
"Vert, can you give me a lift to the Core chamber?" she asked. The Manta did not respond but it left to fly next to the Overwing. They dove to the south pole of the sector and flew up to the platform. Aelita pushed they key and the stairs appeared.
"Do we have to stop some sort of countdown here too?" William asked. The more he saw, the more he actually wanted to know about this virtual world he had gotten into.
"No, but we do need to use this key to get the stairs up to the chamber," Aelita answered. While she could understand the lack of knowledge William had, his continuous questions were starting to irritate her a lot. Cassandra jumped off the Manta and said, "Thanks Vert. You can go now."

The green Manta went back the way it and its passenger had some from. The three Lyoko Warriors continued to climb up the stairs.
"Hurry up, the first shield layer won't last for much longer!" Jeremy rushed.
"We're on our way, Jeremy!" William huffed. The heavy sword was slowing him down, but he did not know where to put it. The two girls were a bit ahead of him and he had to rush quite a lot to keep up. Suddenly his sword fell off his shoulder and got stuck in the ground and refused to get up.
"You can't be serious," William snapped, trying to lift the sword up. Aelita and Cassandra stopped to see what had happened. Cassandra left herself to crouch after landing on the stair and observed the situation.
"Oh, great," Aelita said quietly. Cassandra looked at the pink-haired girl and then back to William.
"Go on. We'll come behind you," she told Aelita and went back to William. Aelita kept going on. Soon she could hear the Creepers moaning and shooting.

William chuffed in frustration. He felt disappointed for his part going so unwell.
"Let's lift it together," Cassandra told him. William looked at him and saw the neutral mask Cassandra nearly always kept. He could still catch a glimpse of compassion in the expression and decided to not turn down Cassandra's help.
"One, two, three, now!" Cassandra said, and they tried to pull the sword up. "It's… getting… up…"
"A little bit more," William noted, seeing that the sword was nearly out of the ground. Then it rose to the air.
"There!" Cassandra sighed. "Now let's get going or we'll miss the whole party!"
"Party?" William repeated, not sure if the word was the right one to be used there. He had to leave the matter be and get going behind Cassandra.

Meanwhile Aelita had reached the Creepers and kept destroying them as fast as she could. Then the first shield layer fell apart.
"The first shield layer is lost! Cassandra, William, hurry up!" Jeremy shouted. "Just where are the others?"
"We are hurrying up, Jeremy!" William noted. They reached the Core chamber and went to the stairs where the Creepers were.
"I'm going up! Take care of the Creepers on the lower level with Aelita!" Cassandra told.
"Okay! Let's get into action!" William said and rushed past Cassandra. Aelita kept throwing the Energy fields and Cassandra unsheathed her sword as she went past her and William. At a certain point the sword suddenly morphed and became wider, more like William's sword. Cassandra sliced the Creepers as she passed them by. William noticed this and could not help but watch awestruck how Cassandra got rid of the Creepers. Then one Creeper hit him.
"Ah!" he exclaimed and looked at his sparking shoulder.
"You just lost 20 life points, William. Be careful!" Jeremy notified.
"Copy that," William said and returned to destroying the monsters. Aelita got hit, too.
"You be careful too, Aelita. You're running out of life points!" Jeremy told.
"I know that," Aelita said and readied a new Energy field but got hit and devirtualized.
"Aelita!" William shouted.
"She got devirtualized and returned back to the scanner. Keep destroying the Creepers, quickly!" Jeremy commanded. Aelita slumped to the elevator and went to the computer lab.

It took about a minute for William and Cassandra to destroy the last Creepers. When that was done, William climbed up to meet Cassandra.
"I could swear your sword was way thinner when you saved me from that Scyphozoa thing," he noted.
"It actually was," Cassandra told and let her sword morph back into its thinner self. "I can alter it in any way I want to. While I normally prefer it as a sabre, sometimes I just need some other sword to be used. Like just now, I turned it into a Zweihänder to slice the Creepers fast. Sabres aren't ideal for that."
"I see", William said and took a small glimpse on his sword. "So what sword is my sword?"
"As of what I can tell right now it's a Zweihänder. Was it just my eyes or is it weighing you down?" Cassandra asked neutrally.
"It does weigh me down," William admitted. "It's too heavy for one hand."
"Zweihänder is two-hand sword. Actually, when its name is literally translated from German to English, it mean 'two hands'. Yours is probably a Zweihänder of Schweren Schlag type. Such Zweihänders are heavier than normal ones. You've got a tricky sword to use," Cassandra noted.
"Could you teach me a trick or two for my sword? I mean, you do excel at swordplay so I thought you could help me at it," William said, though his words became hasty when Cassandra turned to look at him with the previous anger seemingly rising up. He feared he had already crossed the close line when Cassandra gets angry. The girl looked at William's sword shortly and turned to look into his eyes, imperceptibly turning her expression inscrutable.
"Perhaps. I'm not familiar with Schweren Schlag Zweihänders, but I think I could teach you some basic Zweihänder maneuvers. But not today," Cassandra said, crushing William's sudden glad expression quickly. "Get back home and let me think about it."

William felt disappointed. Cassandra did not seem to care about him very much anymore. Some part of him thought that the girl did not even want to see him anymore. He looked at the receding back of the girl he had once learned to know. That girl seemed to be gone.
"Materialize William!" Jeremy executed. William looked at himself turning into pixels and after a short flash of black and red he found himself leaning to his scanner. Odd exhaustion ran through him again, just like last night when he had been scanned. Meanwhile Jeremy and Aelita were calling the others to withdraw the call-out.
"Ulrich, the Core of Lyoko has been saved. You and Odd don't need to come here anymore. But we'll have meeting at the lab this evening, okay?" Jeremy called Ulrich.
"Okay, I'll be right there," Ulrich said, rising from the chair and going to the door.
"But-" Jeremy begun but Ulrich hung up already.
"I'm not finished speaking to you!" Ulrich's father yelled.
"Well I finished listening," Ulrich said and closed the door behind him, leaving his father all alone in the principal's office.
"Yumi, everything's fine now. We managed to pull off the mission," Aelita told Yumi on the phone the same time.
"Oh, good. That's a relief," Yumi said, exhaling.
"Let's meet at the factory in the evening," Aelita told.
"Okay," Yumi said. Aelita hung up and Yumi left to return to her room.
"Where are you going? Weren't you leaving?" Hiroki asked.
"Aelita managed to take care of it for me since you didn't let me do it myself," Yumi said, letting her anger to be slightly heard.
"Odd, where are you? Are you not at the factory?" Ulrich called Odd.
"Why should I be there? I'm in the finals!" Odd noted.
"Didn't Sam tell you?" Ulrich asked.
"Tell me what?" Odd asked.
"Tell you to go you-know-where. X.A.N.A. attacked the Core of Lyoko but others managed to stop it," Ulrich told.
"Oh, I see," Odd said and hung up. Samantha finished her course.
"I'd like to see you top that!" Samantha told Odd.
"Sam, why didn't you give Ulrich's message to me? It was really important!" Odd asked.
"Important? Oh…I'm sorry, I just…I just really wanted you to stay. We're so lucky to be together again, even if for day, and I'm leaving tonight," Samantha told.
"I know how you feel Sam, but…there was something I had to do," Odd told.
"Even more important than hanging out with me?" Samantha asked.
"Unfortunately yes," Odd answered. "But I already missed it."

Jim whistled and announced the next contestant, Odd. Odd went to make his last course, saddened by how things had turned out. Samantha was sad, too, as she saw how disappointed Odd was about this. Ulrich came just in time to see the situation. He did not need to ask what had happened, so he just sat down and watched as Odd skateboarded without the joy from the previous rounds. Samantha did not sit down. She just watched Odd doing his greatest tricks. It was over quite soon and Odd went to sit next to Ulrich to wait for the results of the contest.
"We'll have a meeting in the evening," Ulrich told.
"Okay," Odd answered.
"Hey, listen, I'm sorry I didn't tell you," Samantha said but Odd turned his head away from the girl. He could not believe that Samantha had neglected to tell such an important message. Samantha looked at Ulrich who silently made clear that he was going to stay out of the situation.
"And now the results of the contest!" Jim shouted and the chatting crowd quieted. "The winner of this skateboarding contest is Samantha Knight!"
The crowd cheered.
"Congratulations," Odd said emotionlessly.
"Thanks," Samantha said quietly. The victory did not seem so great anymore, not with her in decently bad terms with Odd now. Jim told her to come and get the trophy.

In the evening the Lyoko Warriors gathered to the lab.
"So why did you call us here?" Yumi asked.
"First of all, we found Franz Hopper, but we can't materialize him. He's out of our reach," Jeremy told.
"Is there anything we can do?" Ulrich asked.
"For the time being, no," Aelita told.
"Is there anything else you want to tell us?" Odd asked.
"Yes, there is," Jeremy answered and moved his chair to show the supercomputer's screen and Cassandra's communication window.
"What?" Ulrich exclaimed.
"Who are you?" Odd asked.
"The name's Cassandra," Cassandra told coldly.
"When did you show up?" Yumi asked.
"Today. She saved me from a weird jellyfish on Lyoko," William told.
"The Scyphozoa," Aelita said.
"The Scyphozoa showed up to you?" Ulrich asked William.
"Yeah. I had been separated from Aelita at that point," William told.
"Okay. But why are you on Lyoko?" Yumi asked Cassandra.
"I'm here on Lyoko because I can't get out from here," Cassandra answered with a nasty tone.
"She refused to let me materialize her," Jeremy told and turned look at William. "But William, I've understood that you and Cassandra have some common history. Am I correct?"
"You are. We were in the same class in my previous school," William answered.
"Well I'm not attending it anymore either. Lucky you, you can still study and I'm stuck here," Cassandra said bitterly. "I guess this still beats being with my parents."
"What happened?" William asked.
"We can say that my parents found out about how, ah, close we were and decided to take me back even though you had already been expelled," Cassandra said, letting irony flow through her whole essence. "After that X.A.N.A. came, helped me to get away and took me as the general of his army."
"You work for X.A.N.A.?!" Ulrich exclaimed.
"Excuse me, but would I have saved William earlier today if I worked for X.A.N.A.?" Cassandra asked. "Use your brain, you have them for a reason!"
"Then why did you say that…" Ulrich begun.
"X.A.N.A. took me to his army and I took everything I could get from its training and then left to the neutral shadows until today. Now I'm an official Lyoko Warrior," Cassandra told.
"What's your history, then?" Aelita asked.
"Well, it's complicated," William said and looked at Cassandra, unsure about how much the girl wanted to tell. Cassandra let her gaze meet his and asked, "How much do you want to tell?"
"It doesn't matter to me," William answered.
"Well, X.A.N.A. already approached me earlier today and threatened to give some twisted false memories of mine to you guys if I wouldn't return to the shadows," Cassandra told and looked at the other Lyoko Warriors. "How much do you want to know? Synopsis, shortened version or the full story?"
"Why not the full story?" Jeremy asked.
"We'll have to divide it for many days," William noted and Cassandra nodded.
"I think it's okay," Yumi noted.
"Agreed," Aelita said.
"It would be interesting to hear about your past," Odd said, glancing at both Cassandra and William.
"Sure, why not? At least there would be something more than just the fight against X.A.N.A. here then," Ulrich noted.
"Shall we begin right now?" Cassandra asked William.
"Where should we start?" William asked.
"I think it would be the best to begin from when you first came to Riverain," Cassandra suggested.

William nodded. "Yes, that's a good idea. Let's see, the day when I came to Riverain…"

/Code Lyoko (c) Moonscoop, Cassandra Delorien, Riverain and the rest of its original characters (c) Me/