Title: Ghost of you.

Number of parts: 10/?.

Pairings: Ninth Doctor/Rose Tyler; Tenth Doctor/Jack Harkness; Clara Oswald/Olivia Baxter (OC).

Synopsis: "Maxence's results were similar to Peggy's but his genetic code was presenting some interesting particularities that needed to be studied to find the reason why it was so different."

A/N: The characters and the universe don't belong to me. All rights goes to Russell T. Davies, Phil Collinson, Susie Liggat, Steven Moffat, Chris Chibnall and to the BBC. Everything else belongs to my imagination.

CHAPTER 10

Jack was highlighting the most important data from the results given by Tegan. He was remarking the same details that Colin had noted earlier – details he wouldn't share – and come to the same conclusions. He was alarmed by the risks there were for Maxence to die from the virus so he sent a message to Liv and Zach for them to keep a closer eye on him and be sure he wouldn't get in any trouble, more than he already was. This done, he worked on the DNA data he had gathered. Maxence's results were similar to Peggy's but his genetic code was presenting some interesting particularities that needed to be studied to find the reason why it was so different.

Maxence's DNA wasn't entirely corrupted by the virus. The four proteins were still present and mixing themselves with the four new ones in a perfect harmony. Maxence was clinging to his humanity like a drowning person would cling to the lifesaver that came for them. Whether it was a good thing or not, Jack couldn't tell. His friend and colleague's side wanted to believe it was because it meant that Maxence wasn't dead, but the other side of him was having mixed feelings about it. What if they couldn't reverse the process? What if Maxence was stuck with this mutated DNA? Would the nightwalker's side be dominant and let him live in this awful condition? Or would it be a perfect mix allowing him to have a better life?

Jack isolated three DNA sequences – one fully corrupted, one normal and one mixed – for a future study. He also had Peggy's sequences but he hadn't learnt much from them. Maxence was a much more interesting object of study. No offense to the man. Jack first chose the corrupted DNA and tried to determine what could be their role in the human system. Every strand of DNA had a particular function in the body. It was composed of four nucleotides: cytosine, guanine, adenine and thymine. All of these were forming the genetic code of a person according to the way they were arranged. It was all mathematical and almost unpredictable. But that was the funniest part of the job: solving the unsolvable.

Clara knocked on the door and Jack opened it to her. She was coming to help him with the proteomics, with the identification of the new molecules composing the nightwalkers' DNA. They didn't exchange a word. They only shared their work and began looking for new clues. No visible answers on the corrupted strand of DNA so Jack picked the mixed one. That's when he noticed something he hadn't before. The beginning of something it seemed like. The moment everything started going wrong. Thymine and adenine were working together like an inseparable team, as well as cytosine and guanine. The combination for a strand could be infinite but those four could only be combined with each other. However, on this strand, everything was mixed and it was the reason why the DNA was so messed up.

Jack looked closer at a molecule of thymine, one of the most essential molecules in the human DNA. It was having a strange form and it was changing under his eyes. The thymine was losing its original form and mutating to adapt itself to the other nucleotides. It wasn't anything new. It was just the molecules changing and rewriting the human DNA. A sort of evolution, in the wrong way. It was making Humanity stupid and aggressive, back to some twisted primary instincts from another era. Something must have triggered this sudden mutation that usually took ages to appear. It was progressive and not so immediate unless something was speeding the process. Something strong enough to change Humanity so radically.

All this new information was written down on a paper that was lying around here. The blood and DNA were showing mutations. They were slower than they should be since the nightwalker in question was refusing his condition. Jack would need a 'complete' nightwalker to compare the DNAs and see how someone clinging to his humanity could maybe be the key to a cure that would save the world. However, he doubted that anyone would want to go back outside now and with the lockdown that wouldn't come to an end any time soon, it wasn't making any mission possible. It meant that they would have to do with what they had by hand. It was more than they could have expected five years ago.

Jack drew his attention back on the other molecules. They were having the same reactions. None of them was spared by the mutation. He added it to the notes. He re-read them, trying to get where this was all leading him and he realised something important about DNA. Something he should have thought of when he had seen that mutated DNA. There was one thing that could cause such a quick reaction and nightwalkers were running away from that thing and needing it all at once. He should have realised it sooner. When thymine and cytosine were mixing each other, it was creating a dimer that was causing kinks in the molecule. That's how cancers started. And the noctiagus was like a non-lethal cancer.

Many cancers were curable when taken in time. It took an awful lot of time to create such process as chemotherapy. How much time would it take to find something that could be working against the noctiagus? They had been working on it for five years and were only finding out how the virus could have come to life. Finding something to cure it or, at least, to reduce the symptoms and give the infected people a better life, would take even more time. It meant that the world would come to an end before they could succeed. It also was to fear that Maxence wouldn't make it until they found something that could relieve him. He needed to let go of his humanity and they all knew he wasn't gonna do this. Rose was gonna make sure he would never let go of it.

Jack sighed and opened a new mail on the private network Zachary had created for them. He quickly typed his observations to send them to Tegan. He specified that it was useless to send them to Clara since he was working with her at the moment but they could be transferred to Rose. She would be happy to hear her husband was still inside that shell currently wandering in the cage downstairs. He added that the UV lights had to be turned off immediately. He would explain the reason in the complete report he would write later.

"This is fascinating," murmured Clara. "Absolutely fascinating."

"Are you speaking about the mutation or about the virus?"

"Both. The way they are working… It's bloody fascinating."

"Yeah. You might have mentioned that."

Clara had her eyes riveted on the microscope before her. She was observing the virus devouring the cells around it and pushing away the white cells trying to defend Maxence against the infection. It wasn't working very well on both sides. It was a never-ending battle.

"It happened during an eclipse," she said.

"Yes."

"And the DNA can be corrupted by UV lights."

"Yes, but it hasn't last long enough. It takes ages to change a DNA, not just an hour."

"It still happened during that hour."

"In my opinion, it was caused by a human hand. The eclipse was just a coincidence."

"We gotta find the patient zero."

"We have to try. To save Maxence."

"How can we do that?"

"I know someone."

Jack flashed her a bright smile and Clara rolled her eyes. Everyone knew how Jack had gotten so many acquaintances. It was no secret to anyone. He could get anything from anyone because he could be very convincing when he wanted. This was rather dirty in Clara's opinion but she hadn't refused some advices to make things go farther with Olivia. Advices that hadn't worked in the end for reasons Jack ignored, reasons she would keep silent until the day she died.

"I'll talk about this to Tegan first; I need his approval before doing anything."

"Speaking of him… You seem very close lately."

"I've just given him some relaxation lessons."

"Jack!" exclaimed Clara, offended. "He's our boss now."

"He asked for it," shrugged the former Captain.

"T asked you to… I don't believe this."

She knew Tegan well enough to not believe Jack's words. The man was too shy and cruelly lacking of self-confidence. Such an indecent offer like only Jack could do would have made him blush and stutter so hard that he would have run away before any answer left his mouth. She didn't see him accepting to have sex with Jack. Unless... His sudden promotion to the highest responsibility of this lab had him so anxious that maybe, just maybe, he would have taken the offer just for one night.

"You've tried with Max too?"

"He always refused."

"You're disgusting."

Clara threw a pen at him. He caught it, laughing, and put it aside. After all, she asked and he had answered in all honesty. Why would he lie? He had nothing to hide.

"Wanna know why Colin is avoiding me?"

"Colin's a sociopath but an excellent scientist. He shouldn't be out of this team."

"He was bullying T until I found out and stopped him. He wouldn't go after me. He's too scared."

"What have you done to him, Jack?"

"Just showing him another side of himself."

"No?"

"That's what he said at first. He changed his mind."

"It'd be faster to ask you who you didn't have sex with in this building."

"You," replied Jack with a grin. "Olivia, Rose, Max. Zachary gave in the first day, said this probably was his best experience. Mickey refuses categorically. Martha wouldn't say no if she wasn't so loyal to him. I think that's all."

"That's quite a long list for you."

"Wanna take your name off of it?"

"Keep dreaming, Captain. You won't have any of this."

She pointed to her body and they both burst out laughing. It was nice to be laughing again but it also felt weird in the heavy atmosphere surrounding them but it also allowed them to relieve some of the tension that was on their shoulders. A guilty pleasure they couldn't refuse in those dark times.

x

Allegro was sat on the camp bed, his back on the glass wall his cage was sharing with Maxence's, and he was keeping still while Rose, Adam and Liv were working on him. He had chosen to have his back on Maxence not to see him wandering in his cage and observing them with his head tilted on the side as he tried to understand what was going on. It was making him rather uncomfortable to be a witness of what could happen to him. The virus was in his system. He wasn't showing any symptom but it didn't mean he wouldn't suffer from them later. He wasn't a scientist but had seen enough of them working to know that the symptoms could come later. He had seen Maxence turn into a nightwalker when they were out. He had seen his pain and horror and despair as something stronger than him was taking possession of his body. Allegro didn't feel ready to go through something like this.

He was quiet as Olivia was doing the blood tests, filling tubes of his blood and adding them in a sterilized case, as Adam took them away to his lab, as Rose was taking samples of hair and skin. It felt weird to be the Guinea pig they were working on. They were as silent as he was. It was driving him mad that silence. It was as if he was dead and they were working on his body. If only they were making observations out loud! It would break that heavy silence he already hated though he was gonna stay here for a long moment. At least, in the tent, he had Liv who was coming and talking to him. She was here today but she was in no mood to chat. Two man down, it wasn't something good for them but maybe it was how they would find a cure. Rose and Adam were gone now and Liv was preparing the needle with the tiny sensors. Zach had made sure the settings were good. They only had to connect Allegro to the system.

"It's like a vaccine," explained Liv. "It will hurt a little and you'll have a small bump for a couple days."

He nodded and rolled his sleeve up to the maximum so Liv could have access to his upper arm for the injection. She cleaned the area and injected the sensors inside his body. That was it. She was done and she would leave. He would be alone to face his future. He wouldn't beg for anyone to stay around but he would highly appreciate it if Liv was staying. She went to the airlock and picked a box she brought back inside. She dropped it on the bed.

"You'll find pyjamas and personal belongings in there. You can even watch movies via the interactive screen. You just have to log in your personal space."

"Thanks."

"Someone will always be around if you need anything."

"Okay."

The UV lights in Maxence's cage were turned off and the sudden lack of light made them look in the other room to see what was going on. Maxence was looking up, confused. He suddenly lay down on the ground as if it was gonna bring the light back. Liv walked to the intercom.

"Zach, what is going on?"

"Sorry, I don't have any explanation. The order came from Tegan."

"He just told you to turn off the lights?"

"Yes."

That was weird but Tegan surely had a good reason for this. Allegro and Liv watched Maxence. He crossed his hands behind his head and was looking at the ceiling. What was he seeing in the dark? What was going on in his mind?

"Can we… like make this wall opaque?" asked the guard placing his hand on the wall behind him.

"I guess we can. Let me see."

Liv opened the interactive wall and selected the settings. She went into the walls category and changed the settings. The wall became black and hid what was happening in the other cage. It brought guilt and relief to his heart. Guilt to feel so relieved because he wouldn't see what he would become in the near future. If the symptoms showed up. For now, he was just a prisoner until someone decided he was no danger to anyone, but with the virus in his system, he was contagious and, consequently, he was locked in quarantine until he was cured.

"I'm sorry," he apologised. "It's just that…"

"You've seen his transformation and it's scaring you."

"Yeah."

"It'll stay between us. Or you can speak to someone. We'e got someone in here."

"I'll be alright for now."

"Ask Zach if you need anything."

"Will do."

Liv gave him a sorry smile as if it could make anything better and take him out of this cage. He gave her another smile in return anyway. It wasn't her fault after all. She was only doing her job and that was when he had done his that he had gotten infected. Sometimes, being careful was not enough to protect oneself against the biggest threat the world had ever seen.

x

There was someone in the cage with him. He had first heard the airlock and now he could hear the distinct sound of a person moving in a hazmat suit, a person who was carrying stuff around. He didn't move from his spot. The ground wasn't very comfortable but he would rather be there than in the bed. He hated the bed. It wasn't comfy, nor warm and it was lacking of something he couldn't name. Plus, no matter how hard he tried to sleep, he just couldn't fall asleep. So, it was better to lie on the ground and observe the ceiling. He couldn't do that when the lights were on. He preferred being in the dark. It was giving him less headaches and he was feeling less dizzy and nauseous since it was off. But he was a little cold to be honest. Some warmth would be great. Some human warmth would be even greater. However, no one would come and cuddle against him to watch a blurry ceiling. Who would hug the monster he had become? Certainly not the cosmonaut who sat beside him.

"Max?"

Max. Diminutive of Maxence. Maxence, that was his name. Doctor Maxence Spitz. He was doctor Maxence Spitz. The astronaut next to him was a man. His voice was transformed because of the plastic helmet around his head. He was hermetically locked in this suit. Maxence didn't envy him. He was locked in a cage but he was free of his moves and didn't have to breathe smell of plastic for hours.

"It's Tegan."

Tegan. Doctor Tegan Smith. Neurologist. Maybe called T or Tenny for short. His little brother, he thought. He wasn't sure. A lovely man, shy and lacking of self-confidence. Handsome with his dishevelled hair and three-pieces suit. Doctor Tegan Smith, currently being the boss of this place.

"Rose thinks you still have troubles with your sight. I've come to check. Do you mind if I do that now?"

If he minded… Of course not. He was half-blind and it was a real disability. He was always on alert and ready to attack. Sometimes, he felt furious for no reason at all and needed to unleash all this rage on the closest person or thing around him. But right now, he was calm. He sat up and let Tegan work on him. He answered to the questions the best he could with his hands. He could faintly see the light Tegan used during his medical exam. When he was done, he placed glasses on his nose. Maxence blinked a couple times and his sight seemed to get a lot better. Glasses. He had always worn glasses. Why did he remember this only now?

"Would you let me change your bandages and inject you new sensors?"

Once again, Maxence accepted the offer. He observed Tegan's moves as the man was taking care of his burnt skin, of the bite in his neck. His hands were slow and soft. He never hurt him, not even when he did the injection. It was pleasurable, to be treated like a human being. But Tegan left after an apology and Maxence was alone again. Watching the ceiling wasn't interesting him anymore so he stood up, leaning on the wall to keep his balance. Sometimes, it was really hard to be standing. He walked to the wall and opened its interface. He entered his username ( ) and personal password (crcd120264) and went to his professional space. They had updated it. He had access to all the results of all the exams his team had done. Even of the tests they had done on him. He titled his head on the side, trying to understand what he had under his short-sighted eyes.

In those results, he found the reason why the UV lights had been turned off. It always had had a bad effect on a human body and Jack had found out that the lights were increasing the symptoms. Since they were off, his mind was clearer. In his opinion. He felt less confused, but maybe it was just a good phase. Maybe it would be worse later. But right now, he felt clever again and could work and help his friends. Jack was thinking it was a virus created by a man's hand. A man that had lost control of his invention at the moment of the eclipse, which had led them on the wrong path. He was requiring the help of a couple of special detectives specialised in finding the unfindable: Donna Noble and Camden McCarson. Maxence did a quick research on them. They weren't described as nice people – Camden was called a "brilliant but incredibly rude detective" and Donna was a "sarcastic sidekick" – but everyone was content with their work. It was worth a try.

The feeling of wellness he had had didn't last long. He opened a window with his vital signs when the first signs of weakness showed up. It was almost imperceptible at first, but he felt it anyway. An oppressive feeling in his chest and a certain stiffness in his left arm. Moving it was impossible without pain. His vital signs confirmed what he was thinking: erratic heartbeats, short-winded, pain in the chest. It was all clear. He pressed his right hand over his heart and used the left one to hit the wall. Zachary was here, sleeping again. Maxence needed to wake him up. He slapped the wall harder as the pain crushed him. He wanted to yell for help but his voice was gone. All he could do was slap this wall hoping it would get someone's attention – why wasn't the alarm ringing already? – while his strengths, his life, were abandoning him…