"Have you found out anything about our guest?" Jack asked Martha while Gwen pulled up the boy's cell on the CCTV so that she could keep an eye on him during the meeting. "Like, I don't know, perhaps a name, for starters."

Martha shook her head. "I could probably extract an identity from his DNA once I do a full examination, but even that's not a guarantee. What's left of this equipment is, to be blunt, not quite as good as it might be. Our DNA sampler is outdated even by early 21st century standards."

"She did find that he's not much more than a lad," Gwen interrupted as she adjusted a dial. "Approximately 21 years old, I think was the determination." She frowned. "At times like this I miss Tosh. She had a way with computers, that one, that I just can't duplicate."

"Right," Jack said. "How about we leave the critique of the facilities for another time and stick to what we do know. I couldn't get much out of him either. He seems to be suffering from the delusion that he's stuck in a bad American crime drama film and that yours truly is the stereotypical rogue cop who will stop at nothing to get the answers he wants."

"He's not far off the mark," Gwen said flatly.

Jack ignored that. "There's a blank spot in his memory; he doesn't have any idea what happened to him between arriving at the residence of a girl called Paige and awakening in the tombs. His movements are slowed down, he has headache and he appears to be ill."

"Sounds like he had one too many with the boys last night," Rhys commented.

"Precisely. Except that going out drinking doesn't generally result in being infected with dark matter. Martha, when you do your examination, I want you to search for evidence of drug and alcohol use. The odds are we won't find any. Either way it'll help us tell the story of how he became infected, and why." Jack frowned. "Something else, too. This girl Paige… whatever happened, it's causing him to shut down. I used my trademark wit and genteel manner - " - Martha and Gwen both raised their eyebrows at him - "Well, my wit anyway. The point is, I was able to get him talking but as soon as I began probing as to what exactly happened he became sullen and defensive and I was unable to get anything further out of him."

Martha nodded. "He must have been exposed to some traumatic event, paving the way for the Black Guardian to invade his being."

"Right. Memory traces would provide invaluable here. If we can see through his eyes what happened to him, we might be able to determine the purpose of the invasion. The Black Guardian wants something with him, but what?"

Martha frowned. "I'll try, but with this equipment - "

"Again with the equipment." Jack turned towards Gwen. "Gwen. I need you to prep the boy for his examination. Go down to the tombs, get him to trust you. Don't worry about getting him talking, just convince him that we're not here to hurt him further. We need his resistance to our probing as low as possible if we're going to get the information we need."

"Straight away." Gwen tilted her head up at the monitor, which she had finally got working. The boy was curled up in a ball on the floor, his shoulders shaking. "He looks like he could do with a friend anyhow." She walked off.

Martha and Jack exchanged glances. "Are you thinking what I'm thinking?" Martha asked.

"I gave up telepathy a while ago. What are you thinking?"

"I'm concerned about Gwen's overempathy with this boy. She seems to refuse to understand that the dark matter may make him not act like himself and that he may actually be dangerous. It would be so easy for the Black Guardian to cause him to do something to her."

Jack frowned. "That's a risk we have to take. We need to gain his trust before we can neutralize the threat."

Rhys slammed his hand down onto a counter, making the computer systems shake. "I won't stand for the way you talk about my Gwen," he said. "Either of you." He turned towards Martha. "She may have a big heart but she's nobody's fool and you speak of her as if a lad from bloody America can easily pull the wool over her eyes just by shedding a few tears. And you, Captain Jack Harkness or whatever your name really is… this may all be a grand experiment to you but my Gwen is not expendable, do ya hear me? Her life matters just as much as that young one in there."

"Of course it does." Jack's voice was neutral. "I think you've misunderstood me. The Black Guardian only interferes with the lives of people who have the capacity to take amazing steps forward for all of mankind, trying to throw the universe into chaos, stop us from making progress. Gwen's clear love for a boy she's never met, a boy who for all we know belongs in the distant past or far future, just might be the key to saving the world in some way that we can't see. Her conversation with him down in the Tombs isn't trivial. It's vital. To everything."

JJ shoved his hands over his ears. "Shut up!" he shouted, then realized he was shouting at the voice in his head. He whimpered and looked up. "I'm going crazy," he whispered. "Oh God."

Footsteps sounded down the hall. Lie down and pretend to be asleep, the voice in his head whispered, and he wasn't sure if he was telling himself what to do or if someone was ordering him around. Either way, he had to do it cause if the cops knew he was losing his mind, he didn't know what would happen to him. He put his head down and closed his eyes, but as soon as he did he saw himself cradling Paige's dead body and no amount of blinking made it go away.

He heard the cell door slide open but he didn't care. It didn't matter, nothing mattered. He wanted Paige but he didn't deserve her.

"You're poorly, eh?" it was a woman's voice, Welsh accent. JJ had heard it before somewhere but he couldn't quite remember.

He lifted his head slightly despite himself. The woman was pretty, with dark hair that reminded him of Paige, what she might be like when they were older with kids of their own. He blinked back tears. "You the one who arrested me?" he groaned.

"In a manner of speaking." Gwen squatted by him. "You remember, then? Us finding you facedown down by the Bay?

The Bay? Where the hell had he ended up? "I'm so sorry," he mumbled. "I mean, I… I don't remember what I did but it must have been pretty bad cause P-Paige…" His shoulders shook and he felt that same wordless pain as before.

"We didn't mind giving you a lift," Gwen told him, pretending not to know what he was really trying to say. "We just wanted to ensure you were safe, that's all." JJ shrugged and Gwen asked, "This Paige, she must be special."

JJ's face trembled but he said nothing. Gwen said, "Let's start again with a proper introduction, eh? Name's Gwen. And yours?"

"Like you don't know." JJ's eyes flashed. Gwen said nothing, just gave him a wide-eyed stare that reminded him so much of Paige he felt like he'd been punched in the chest. He looked away from her, not sure he could hold back the tears any more. "It's JJ, okay?" he said, his voice wavering.

"JJ. Now we're getting somewhere." Gwen's voice was quiet. "How about I tell you a bit about where you ended up?" JJ shrugged again. "We haven't left Cardiff," Gwen told him, "we're just deep underground in a place called Torchwood." JJ remembered the other dude had said Torchwood too but he didn't have the energy to ask what that was. "And you're not in trouble, at least not the sort you're thinking. You're in our custody, yes, but not because you deserve punishment. I used to be on the beat, I know a troublemaker when I see one and that doesn't seem to be you."

"Whatever." JJ's voice was flat.

Gwen sighed. She patted JJ's back, but that made him wince and snap, "Don't - "

"Sorry." Gwen held her hands up. "I need you to pick yourself up off that floor. I came round to take you to the infirmary, so to speak. We need to run some tests, find out what happened before you landed belly down at the Bay."

JJ's eyes widened and for a second he looked terrified. He sat up slowly. Gwen held out her hand, but he shook his head and got himself up. "You got a mirror?" he asked. "I'm sure I look horrible but…"

"The grooming's not the important thing right now," Gwen said, gently. "We want to get you well."

JJ nodded. He let Gwen take his hand and help him pull himself to his feet. Then he put his hands behind his back without being asked. "I know way too well how this works," he said in answer to her raised eyebrows.

Gwen nodded. "With any luck this will be the last time," she said, waiting til she was behind him to take out the timelocks. She was sure he'd never seen cuffs like these before and she didn't want to scare him any further.. "Our doctor'll find what's got you in this state and once we know you're not dangerous we can dispense with these, yes?" She set the cuffs and put her hand on JJ's shoulder, holding him as gently as possible as she led him out of the cell.

Martha already had the exam room set up when Gwen brought JJ in. "This is Martha Jones, the company doctor so to speak," Gwen told JJ. "And this," she said to Martha, "is JJ."

"So we have a name," Martha commented. "Excellent. Let's get him up on the table."

"He's not deaf," Gwen told her. "Do you think you can be bothered to speak directly to him?"

"Right. Sorry." Martha turned towards JJ. "We're going to get you up on the exam table and do some basic scans and blood analyses." She pressed a button to release the restraints, then took them off JJ and handed them to Gwen. "Since we're so shorthanded, think you can work the computer, Gwen? Everything I'm doing'll go right into the software. It'll chime if anything's unusual but I need a pair of eyes looking at it too."

"Right." Gwen patted JJ's shoulder. "Have a yell if you need me."

Gwen took her place at the computer and put on her headset while Martha had JJ lie down on the table. She started with the same scans as before. The computer beeped and warned of abnormally high dark matter. "What's the count?" Martha asked and Gwen told her, "3752." Martha nodded and said, "Down by 3%. It's a start."

Next, Martha took a laser and ran it over JJ's arm so that it could analyze the blood running through his veins. The computer flashed that there was a DNA match with a Jack Deveraux Junior, born September 23, 1995 in the town of Salem in the midwestern section of America. It also again registered high dark matter content. Martha pressed a button and the computer registered that the last known exposure to alcohol was in November of 2014 and the last known exposure to other drugs had been almost precisely two years earlier. Gwen repeated that to Martha, who nodded.

Glad that they were using the headsets so JJ couldn't hear, Gwen asked, "So if it isn't alcohol, what's the hangover then?"

"I'd say we're looking at an energy-based attack. His symptoms aren't chemical in the slightest."

Martha picked up a piece of flexible plastic and began to wrap it round JJ's head. He shuddered and said, "What the hell's that?"

"We need to try to find the source of your headache," Martha told him, leaving out that she was looking for memory traces. She finished putting the band around his head and pressed some buttons on it. It lit up green and the computer reported happy memory traces found and played a silent video of a six-year-old boy opening a guitar at Christmas and running happily into his father's arms. Having established this baseline, Martha programmed the band to search for other memory traces. But when she tried to search for what happened right before JJ was found unconscious, it found only half a trace. The video began to play of JJ walking into Paige's room. Then the computer chimed and a big red box appeared labeled, MEMORY CORRUPTED. Two separate videos played together over each other. One was of JJ heading towards the bathroom of the room and the other was of him staggering around drunkenly.

Suddenly, JJ doubled over. He groaned involuntarily and he heard that voice in his head again. You caused this. You know you did. "No," he moaned. "Please, no, stop…" He threw his hands over his ears, rocking back and forth, squeezing his eyes shut and moaning. The computer warned that his dark matter count was spiking. JJ began to sweat.

"Stop the test!" Gwen snapped. "Look what it's doing to him, Martha, we'll lose him."

Martha nodded. She pressed a button and the test stopped. JJ lay completely still, doubled over. Martha did a scan and said, "His temperature is elevated, especially around his upper back. I would guess that's the source of the infection." She put her hand in front of JJ's face but he ignored her. "JJ? Can you hear me?"

"I'm burning up," JJ mumbled.

"I know. We're going to let you have a rest, all right? Gwen'll take you back to your cell temporarily whilst I finish up some tests."

Gwen took off her headset and came to collect JJ. She could see the tears in his eyes. "It'll be all right," she said softly. "You'll have a lie down, yes?" JJ nodded, seemingly unable to speak. His arms were limp as she pulled them behind his back; he neither spoke nor resisted being cuffed in any way. Gwen wasn't sure the timelocks were at all needed but then again he might try to do something to himself whilst in this state.

"Come." Gwen put her arm around JJ. He let her lead him back to his cell.

Later, after Gwen had got JJ settled back in his cell and told him softly that he was safe and that they were going to get to the bottom of this, she rejoined Martha. Martha was frowning at the computer. "I tried to run a simulated extraction of dark matter," she said. "It's not likely to work but it's the only chance we have right now."

"And?"

"And it's doomed to failure." Martha sighed. "Here's what we know. That attack he experienced was engineered by the Black Guardian. The dual memories - that was because shortly after being exposed to whatever traumatic experience occurred in his girlfriend's bathroom, he was attacked by the parasite and his memories altered. He's essentially been, in a manner of speaking, reprogrammed to believe that he went to her room totally pissed and ended up in police custody. But as the tests show, nothing of the sort happened. It's been nearly a year since he touched alcohol."

"So can we unedit his memories, get the real ones back? Would that drive out the dark matter?"

"Yes and no. The Black Guardian clearly is controlling what he remembers. Most likely he will remember the trauma when it suits the parasite's purpose - that is, when it is most likely to destroy him. Restoring his memory would loosen the Black Guardian's hold on him, but paradoxically, if not done in a safe, controlled manner it might make the dark matter already in him spike further as he is not equipped to deal with it."

"So what do we do?"

"I don't know." Martha tapped on the computer keyboard. "At the risk of incurring Jack's wrath, we need better equipment. If we had the medical facilities of a decade or even of five years ago we might be able to entice the White Guardian to make an appearance. As it is, we have limited resources, and the most limited is time. The episode he had whilst I was examining him is but a small taste of what it will look like as the darkness spreads. The poor boy is going mental, with the help of an evil influence that wants him to break down completely. I'd say we have at the most, 48 hours to save him."

Gwen glanced up at the monitor. JJ was standing with his nose pressed against the glass, breathing heavily, tears running down his face that he likely was not aware of. She shook her head, sadly.

"There's a way you haven't thought of. It might break all the rules of Time but what's a few rules when the fate of the Universe and of one young kid is at stake?" Jack said later, when Gwen and Martha filled him in. "We have all the time time in the world, really. All we have to do, is jump back a few years." He glanced at Martha. "How would you like to meet your predecessor, Dr. Owen Harper, during a time when he was fully and unquestionably alive?"