In the computer lab, Aelita, Jeremy, Josh and Yumi waited for Ulrich and Odd to get back from break. Aelita and Yumi were sitting off to the side playing Go, while Jeremy was talking away at the computer putting the final touches on his program to track Xana's location on the network. Josh was leaning against the wall of the lab with a notebook in hand, working on calculations for locating Franz Hopper on Lyoko. The four heard the elevator and all looked towards the doors as they opened, revealing Odd and Ulrich.

"Welcome back!" Aelita said still playing Go. "Two weeks without us. Not too long?" Ulrich asked, laughing a bit. "Did you miss me a little, ladies?" Odd asked, directed towards Aelita and Yumi. Jeremy and Josh both shot Odd a look, like what about us. "Forget it. You could've stayed away three weeks! XANA attacks: zero." Yumi said, smiling. "Well, a nice, quiet summer, huh?" Odd asked. "Sort of, ever since Xana managed to escape the super computer into the network, there hasn't been any activity on Lyoko at all." Jeremy said typing. "No news is good news, right?" Ulrich stated. "That's what you think. I trust Xana as far as I can throw him. Which is why I spent all summer when not busy with training, programming a new version of the superscan to try and sniff out Xana's activity on the network." Jeremy stated bring up its window. "Okay? That's great, I guess? But how is that going to help us?" Odd asked, not really understanding what it did. "Well, firstly we can try and figure out what Xana is doing on the network, and what his new goals are." Jeremy replied. "Then you can send us in to crack a few heads?" Ulrich asked, understanding a bit better than Odd did. "Basically. But it's going to take a lot of work to get you guys into the network, especially since the Digital Sea is just an extension of the network into Lyoko." Jeremy said. "I have been working on figuring out how to locate Franz Hopper on Lyoko, since he has to be here somewhere." Josh said.

"Well, let me remind you, we have to pick up our class schedules before lunch. So let's move!" Odd started still standing near the elevator. Josh, Jeremy, Odd and Aelita walked into the elevator getting ready to head back to campus. Yumi stopped Ulrich before talking to him. "Ulrich, Wait a second. You know, I did a lot of thinking during the summer…and I have something important to tell you." She said, trying to stay quiet so the others didn't hear. "Okay. Go ahead." Ulrich said, smiling a bit. As Yumi was about to speak Josh spoke up. "Are you guys coming?" He asked as the four of them stood in the elevator waiting. "Be right there." Yumi yelled over to Josh. "I will tell you later." Yumi said to Ulrich before walking to the elevator.

The group went back to campus before heading to the administration building to pick up their schedules. Jeremy, Josh and Aelita were in the building while Odd and Ulrich waited out in the outdoor hallway. "So what did Yumi want to talk to you about?" Odd asked, being a bit noisy. "I don't know. She just said it was something important." Ulirch said leaning on the wall. "You think maybe she wants you to ask her to marry her?" Odd asked, jokingly. "Yeah, right! I was going to ask you to be my maid of honor, Odd." Ulrich replied jokingly, before looking to his right and seeing Aelita, Jermey and Josh returning from the office with their schedules. "And now it's time for lunch!" Odd said happily. "Odd, do you ever think about anything but food?" Josh asked, jokingly. "Yes but only when I am not hungry." Odd replied, sounding serious. As the group began to walk towards the cafeteria Yumi happened to be walking to the cafeteria and joined them. As she did, Ulrich stopped and waved for her to stop. "So Yumi, what did you want to talk to me about earlier?" He asked. "I wanted to say that I …" Yumi started to say before being interrupted by William walking up. "Hey, Yumi! It's really nice to see you again. Did you have a good vacation?" He asked. "I will tell you later." Yumi said to Ulrich before walking away with William.

In the cafeteria, the group except for Yumi sat and ate. Jeremy had given Odd his tray while he was watching the program he wrote to track Xana on the network run. Aelita looked over now and then as she was eating, while Odd was eating both his and Jeremy's food. "Jim wants to start up a basketball team this year. Seems he played pro ball." Ulrich said while eating just as Yumi walks up to the table with her tray. "But he would rather not talk about it." Everyone said at once. Yumi sat down next to Ulrich and started eating. "So Yumi, what did you want to tell me?" Ulrich asked quietly. "I will tell you after lunch when we can be alone." Yumi replied quietly, not wanting to tell Ulrich in front of all their friends. Jeremy's computer began beeping as the scan was able to detect a trace of Xana on the network isolated to a system in North America. "Fantastic! I have managed to localize Xana on the network. I am going to head to the lab to find out more. Aelita, want to come with?" Jeremy said, closing his laptop before putting it in his bag. "Sure." She replied, smiling a bit. "Would it be alright if I tag along as well?" Josh asked. "Sure." Jeremy replied. The three got up and walked out of the cafeteria heading for the factory. Odd was still eating his collection of food when Ulrich decided he was going to get up. "Yumi, why don't we go for a walk, then you can tell me." He said a little nervous. "That sounds like a good idea." Yumi said getting up as well before they both left walking towards the woods.

While on the way to the factory with Jeremy and Aelita, Josh slowed down a bit and put a hand to his head, a slight look of pain across his face. "Josh? Are you okay?" Aeltia asked, noticing. "Yea.. I I will be fine." Josh said as they continued walking, as pain slowly became worse.

In the forest, Ulrich leaned against a tree slightly. "So you wanted to tell me something?" He asked. "Yes, I think we've…both been running around in circles?." Yumi began saying. "We have?" Ulrich asked. " One day we're together, the next day we're not… One day you're jealous, the next day I am, and that's why I think we've gotta clear up our relationship. It doesn't have to be now but it has to be soon." She said, sounding upset. "Oh…" Ulrich said jumping, a little bit.

At the factory the group headed down to the lab, while Jeremy and Aelita walked over to the console, hearing it beeping in an alert type tone, Josh walked slowly towards them his hand still on his head. "Uh-oh." Jeremyt said, looking at the screen. "What's wrong Jeremy?" Aelita asked, keeping an eye on Josh and Jeremy began typing to investigate. "It seems as if we have company, Xana has sent a bunch of monsters to Sector Five." He replied. "He's probably mad that we managed to locate him on the network." Aelita said. "That could be, but what does he plan on doing with all his troops.." Jeremy said. "I wonder if that has something to do with my head hurts so much.." Josh said, strain in his voice. "It could be, we should both head to the scanners to go find out." Aelita suggested. "Yeah, both of you head down, I will call the others to come over." Jeremy said typing.

In the forest, Yumi got a call. "Jeremy? Okay, I will tell Ulrich, we will be right on our way." She said before hanging up. "Ulrich, Jeremy needs us at the factory." She said slightly worry about how he was taking the news.

Odd was in his room playing with Kiwi after lunch when Jeremy called him. "Odd head over to the factory, you're needed on Lyoko." Jeremy said. "Okay, I will be right there" Odd said, before hanging up.

In the factory, Aelita walked to the elevator while Josh stumbled to it. "Josh, will you actually be okay to go to Lyoko?" Aelita asked, worried about his deteriorating condition. "I think so, but I honestly don't know." He said, his voice shaky, as the elevator went down to the scanner room. Once they reached the scanner room, they both went to a scanner.

While Jeremey was virtualizing Josh and Aelita, Ulrich and Yumi were taking the elevator down to the lab. "Head down to the scanner room, I am virtualizing Josh and Aelita now, and Odd is on his way." Jeremy said before finishing the virtualization process for Josh and Aelita.

Josh and Aelita virtualized near the edge of the ice sector. Once on Lyoko the pain that was once only in Josh's head spread across his whole body causing Josh to fall to his knees before trying to get up, trying his best to ignore the pain. "Josh, are you okay?" Aelita asked, worried even more than she was before. "I will be fine." He said standing up slowly. Moments later Yumi and Ulrich virtualized next to them. After a few minutes later the group saw Odd virtualize a short distance away from them. "Okay, you need to head to the edge of the sector. And hurry up there seems to be more and more monsters in that strange room." Jeremy said, waiting for them to walk the short distance to the edge of the sector. "I am entering the code now." He said shortly after bring up the transports program and entering the scipo access code.

The transported scooped up the 5 of them and quickly made its way to the center of Lyoko, before entering Sector 5 and dropping the group off. "So where are all the monsters?" Ulrich asked, reaching for his saber ready to fight. "What do you know, they appear to be in some sort of room right before your feet. We have never been there before." Jeremy said, starting to get a good look on the holosphere system. "But.. What are they doing there?" Aelita asked. "How am I supposed to know? You're the ones on site." Jeremy said. "So how do we get there?" Yumi asked. "Access is through the celestial dome. Don't forget to find the key." Jeremy replied as he noticed the count down starting.

The group ran down the opening corridor to a large open room with spread out pillars. "There's the key!" Aelita said point across the room on the wall. "I will go get it." Odd said running off the platform jumping into the air to get to the next, just missed landing on it and managed to catch himself with his hand. "I thought I had my A-game going." Odd said once he managed to pull himself up onto the platform. Josh, Yum, Ulrich and Aelita jump across next landing on the platform next to odd. "I will go." Aelita said effortlessly jumping from platform to platform across the room towards the key. The group watched in shock. "Five.. Four.. Three.. Two…. One" Jeremy said watching the countdown come to its end as Aeltia got to the key and pressed it just as time ran out. "Zero!" She said, "Nice going, Aelita." Jeremy said relieved to see the timer stopped and the core zone not reconfiguring itself. Suddenly all the blocks in the room begin to move up and down randomly. "I think you all better get here ASAP!" Aelita yelled across the room. The group made their way across the room, on the last jump the block Odd was on suddenly dropped away causing his jump to fall short, as the block in the gap he jumped across was moving upwards at a high speed. "Odd grab my hand!" Ulrich said, pulling him out of the way before the block when flying up past both of them. "Looks like you got your Z-game going today." Ulrich said jokingly. "Lay off will you." Odd said, sounding annoyed. Once the group all got to the platform they walked out to the elevator and hopped onto it as it raced by. "I am virtualizing your vehicles at the access to the celestial dome, there are more and more monsters in that room." Jeremy said typing, virtualizing the Overboard, Overwing and Overbike. As the group rode the elevator, Josh fell to the ground. "Josh?" Yumi asked, noticing. "I am… fine. Just been having this strange pain everywhere since I virtualized. Before then I had a horrible pain in my head." Josh replied, struggling to stand back up. "You probably should have stayed in the lab." Aelita said, concerned. "I said I am fine." Josh stated finally standing up.

Once they reached the celestial dome they got onto the vehicles, Aelita got on the Overwing with Yumi, Josh got on the Overbike with Ulrich and Odd got on his Overboard. "So where do we go to some monsters' heads?" Ulrich asked. "Head down to the south pole of the dome, the access seems to be there." Jeremy replied, mentally making a note to develop Josh some form of vehicle later. "Maybe, that's where Xana holds his annual monster ball, because we haven't seen any." Odd said before Yumi noticed a manta heading towards the south pole."Look over there." Yumi said, pointing at the manta that had changed its course to intercept the group on their way. Odd took aim at the manta and fired a few laser arrows but all of them missed. Yumi threw her fans at the manta which managed to slice through it, destroying it. "Do you see the entrance?" Jeremy asked. "Sort of hard to miss." Josh said as the group headed towards the opening which has two sets of jaws opening and closing as if trying to deter anyone or anything from entering. The group entered passing through the opening when both jaws were open, stopping at a lower platform where a spiral staircase on the outside wall lead up towards a blue sphere with two cubes surrounding it.. "So what are the monsters doing?" Jeremy asked. "It looks like they are shooting at some sort of blue ball." Ulrich said. "Well, if Xana want's it destroyed is has got to be important." Jeremy replied. "So go after the monsters while I try and figure out what that sphere actually is." He added typing quickly.

Odd quickly began to go the staircase taking out creepers that were on the edge shooting up at the central sphere. Yumi threw her fans at a manta that was flying around, while Ulrich began destroying other creepers along the staircase. Aelita stayed back near Josh who looked like he was struggling more the closer he got towards the sphere.

As Yumi slowly made her way up destroying manta, two managed to get lucky hits on her, causing her to be devirtualized. Odd jumped off a platform and landed on a manta causing it to begin to shoot randomly trying to buck him off it's back, before he shot it and jumped back onto the platform, but he didn't notice the creeper already on the platform which devirtualized him in a split second.

In the labs Jeremy was typing quickly, as Yumi and Odd came up from the scanner room. "I don't believe it. Ulrich, Josh and Aelita, you have to protect that sphere." Jeremy said bring up new windows to view the status of the sphere. "Why?" Ulrich asked continuing to destroy the monsters. "That sphere is the Heart of Lyoko. The direct access to the core programs of the virtual world, and based on this information, where Josh's program primarily resides." Jeremy said still typing trying to find out as much information as he could. "If the monsters destroy it, Lyoko will be destroyed, Josh as well. Hurry up, the first shield lay just blew." He added getting tense.

As Ulrich continued fighting Aeltia made her way up to the staircase with Josh, who gasped out in pain when the first shield blew. Once Aelita and Josh made it to where the fighting was going on they watched as Ulrich was devirtualized. "Aelita, stay back." Josh said, walking towards one of the remaining creepers destroying it with his blade. "Josh! Behind you!" Aelita yelled as a creeper shot Josh in the back devirtualizing him. "Aelita, it's time to put that training to use." Jeremy said as the group watched on his screen as Aelita destroyed the last creeper but was devirtualized in the process. "Did Aelita just get devirtualized!?" Odd gasped worried. "Yea?" Jeremy said, oddly calm. "But doesn't that mean she's gone?" Ulrich asked, concerned at how calm Jeremy was. "Just wait a second for Josh and Aelita to get up from the scanner room and I will explain it all." Jeremy replied.

Once the whole group was in the lab, Jeremy began to explain. "You see, over summer, Aeltia developed some new powers now that her virtual profile is fully complete. In addition, the normal materialization program works properly now for the same reason." Jeremy explained. "That's great news!" Odd said. "Especially now that Xana seems to want to destroy Lyoko." Aelita added. "Also Josh, I found a lot of interesting data while investigating the core. It seems as if the majority of your program resides there, this probably explains how in the past you have been able to feel Lyoko, sort of know when towers are activated, sense spectors and possessed people, plus it also explains how you were able to easily understand the systems programming." Jeremy continued. "Is that good news or bad news?" Ulrich asked ,not understanding half of what Jeremy was talking about. "Both. It means we at least have a place to start when it comes to freeing me, but it also means it's not going to be easy." Josh replied.