Al was relieved when Ziggy informed him that she had located Sam and would be able to establish a lock on him. Less than three minutes later, he was in the Imaging Chamber, handlink and cigar in hand, surrounded by holograms—including Sam's. Before he could open his mouth to say anything, however, Sam spotted him.

"Al," he started. "This entire leap is driving me crazy! I finally start to figure something out, and then the Doctor tells me something else, and…." He threw up his arms in frustration, pacing a few steps before stopping to look at Al. "I don't know what to do, and I don't think we've got much time. Something's happening to the Doctor, and he keeps telling me he's all right, but I know he's not. It's frustrating." He sighed. "I don't suppose Ziggy has come up with anything?"

"She doesn't have enough information to project a scenario. We didn't get much last time, and of what we did get, half of it didn't make sense. Even if you tell us everything, I can't make any promises. We have to enter anything about the Doctor manually, and Gooshie told me the minute anything remotely related comes up, the entire report he's working on becomes a temporary file. And Tina hasn't surfaced, so we're short-handed. I'd have a talk with her, but I'd be too tempted to join her." He smiled at the thought. "We'd be snug as two bugs in a rug and we might be able to dance a certa—"

"Al!"

Al took a puff of his cigar. "The Doctor's not making much sense at our end, either. He won't tell us everything we need to know, and he refuses to undo whatever the other Doctor did to Ziggy. But I—" The handlink squawked, and he looked at it. He frowned. "The Doctor wants to come into the Imaging Chamber with me. Says he rigged something up so you two could communicate. How he can do that without it interfering with that block on Ziggy is beyond me. Look, before he bursts his way in here, why don't you tell me what you've found out and we'll feed it into Ziggy?"

Sam explained the situation—careful not to make any assumptions, Al noted—and was looking worried by the time he'd finished. "The Doctor says he wants to talk to himself, too," he added. "Thinks they can come up with something."

"But all he's told you about why you're here is that you're really not supposed to be here at all?" Al repeated incredulously. "You don't believe him, do you? This entire situation is completely caca, and neither of the Doctors are doing anything to convince me that they aren't loony tunes!"

"He's been right about almost everything else; what if he's right about this, too? How am I supposed to leap when we don't even know what I'm here to do?"

"We'll figure it out. Gooshie's feeding the data into Ziggy now."

"But it's all theoretical! We aren't dealing with hard facts."

"Depends who you ask, I think," Al muttered. "Look, I—" The handlink squawked again, three times in quick succession, and he looked down at it. Rolling his eyes, he said, "Wait here. I'll just be a minute or two. Seems I need to explain our rules to the Doctor, judging by how he's broken some code and gained direct access into the handlink." He winced as it squawked again. "Why I even let him near Ziggy…." Without waiting for a response from Sam, he punched the appropriate buttons to open the door to the Imaging Chamber and left, closing it behind him.

When he entered the Control Room, the Doctor was wearing an absurd grin. "Ready? I've got it all fixed up."

Al turned his gaze to Gooshie, who looked more than a bit distressed as he tried to stutter out an excuse. "Admiral, he—I—when the—"

"What he means to say," the Doctor cut in, "was that I managed to isolate the audio link that allowed Katie McBain to speak to Sam. All we need is skin-to-skin contact for a visual, so we're set; I only needed to extrapolate the signal and strengthen it, relaying it through a secondary transmitter—your handlink—so I can see what's going on as surely as Sam can see me."

"Ziggy—"

"The audio connection is stable, Admiral, but was uniquely modified to the Doctor's voice pattern and cannot be applied to others. The visual relay connection is temporary and subject to breakage that will not be easily repaired. I estimate it will last no more than twenty-six point two minutes."

"It's a precaution," the Doctor explained, not even flinching under Al's steel gaze. "I think we're in enough of a mess as it is without me changing things on you even further, wouldn't you agree?"

"Ziggy, when do you think you'll be able to project a reason for Sam's leaping in?"

There was silence. Then, "Without the availability of additional data, a likely scenario cannot be determined prior to the estimated termination of the parallel."

"Oh?" Al took another puff of his cigar. "When's that, then?"

"At the current rate of deterioration, I estimate termination will occur in three point six hours."

"What? Then how can we slow the rate that that thing's going to unravel?"

"There is insufficient data, Admiral."

"And it's not unravel," the Doctor corrected. "It'll just stop. Unravel would imply that it—"

"I didn't ask you," Al snapped, losing his temper. He took a few deep breaths before starting again, giving himself time to rein in his anger. "Gooshie, feed every single word you hear into Ziggy. Doctor, with me. We need to talk to Sam."

"Sam, I couldn't find…." Martha trailed off when she caught sight of him. He looked positively ill—shoulders hunched in pain over the console, face pale but still glistening with sweat, knuckles white on hands pulled into tight fists. "Sam?" she called again, uncertainly. "What happened?"

She watched his fingers uncurl and flex, his face relax. He turned to her and offered her a grin. "Why, Martha Jones," he greeted in a jovial voice, "back from the library already, are you?"

Bits of the Doctor, he'd said. Quite a bit, if he could mask his pain that easily. She could see no trace of it now except in his eyes, barring the still pale face. "I couldn't find anything relevant," she answered, watching him carefully. "Wherever the Doctor keeps his books on quantum physics, it's not there."

"No, I don't expect it is. Not exactly light reading, is it, for you lot? I'd keep it in a separate library, myself. Narrows the searches down. I don't expect you've found that one yet?"

"I'd said I only knew of one library," Martha answered, eyes narrowing slightly. "I mean, sure, the Doctor probably has more tucked away, but that's not the point. You're not well, are you?"

"Ah, don't mind me," Sam said, waving the question away just like the Doctor would. "I'm all right."

"Sam—"

"Just some temporal feedback," he admitted. "Nothing serious. I expect being a time traveller who's leaped into a time traveller is catching up with me." He closed his eyes and took a slow breath. "It'll pass."

"Let me have a look at you," Martha insisted. "Come on, sit down."

"That's not necessary. I'll be fine. Right as rain in a minute or two, I expect." He smiled at her encouragingly, trying to get her to believe him, and she almost did—until she saw the smile slip, just for a second, into a grimace.

"Sit," she ordered, pointing to the pilot's seat. "Now." She reached to grab his arm, but he danced out her way, twisting around to the other side of the console before she could blink. "Oh, come on," she said, rolling her eyes at him. "You put up with it last time."

"And that should still stand as proof enough that I'm well, shouldn't it?" Sam countered. "Nothing wrong with me then, was there?"

"Maybe not, but something's clearly changed."

"Oh, I expect once the splicing's through, things will come together as they should."

"Yeah?" Martha looked at him sceptically. "And how would you know that?"

"I had a…bit of a…visit."

"With Al, you mean."

Sam brightened. "Yes! Only, had to slip out of the TARDIS to do that. He can't reach me in here. Primitive technology." He must have seen her face, because he quickly added, "I mean, compared to this." He waved an arm around him. "Cutting edge for the late twentieth century, sure, but it can't compare to this."

"I'd still like to have a look at you."

"I'm fine. I've been doing this for, oh, I dunno, five years or so now. Least, I think it's been five years. It's a bit hard to keep track. But last time I was at the Project, it was 1999. Which would make it almost five years. So I have some experience with this."

"With leaping into other time travellers?" Martha folded her arms, not buying it for a minute.

"Well, not that, exactly," he confessed. "But I've leaped into a chimpanzee."

"You what?"

"That didn't go as planned, actually," Sam told her, looking off to one side in thought. "I was supposed to make sure Bobo was accepted into the space program, but, well, long story short, Bobo ended up with the brilliant Dr. Leslie Ashton, who built a sanctuary for orphaned and ex-research chimps." He looked back at Martha, who was still staring at him. "It's one of the clearer leaps," he defended. "I don't remember everything from them. Just pieces. And frankly, I'm glad I don't remember what caterpillars taste like." He made a face. "Remember it was nasty, though." He paused, then added, "But, you see, it's the Swiss-cheese effect. I've got holes in my memory. If you were to ask me something from my own time, or a detail about a previous leap, I might not even be able to tell you the answer. I don't have any control over what I remember and what I don't."

"But…then how can you—?"

"It's not easy. I mean, there was a time I didn't remember my own last name, let alone my brother. But I expect it's like your travels with the Doctor."

"What?" Martha uncrossed her arms and walked around to face him, and he didn't move away. "Why do you say that?"

"Because I never know where I'm going to end up, and half the time, it's dangerous. I've leaped in to hear gunshots less than two minutes later. One time I even leaped in holding the gun. I've nearly been killed on some leaps. But the thing is, so have you, haven't you? You've faced dangers and survived." He studied her face. "Yes, you must have. And not just on Earth, I'd reckon."

Martha felt her mouth twitch into a smile. "You're right," she acknowledged. "But I still love it."

"And I love what I do. Really. I know how much good I'm doing. It's just…. I want to go home."

"Can't you?"

Sam shook his head. "The retrieval system doesn't work. They've modified it, but…." He trailed off.

"That's terrible!" Martha exclaimed. "Isn't there anything anyone can do?" He shook his head again. "What about the Doctor? Can't he fix it if he's there?"

Sam looked startled. "Well." He stopped. "You know, I'm not sure." He stopped again. "He probably could. Well, no probably about it, not really. He could. Perfectly capable, I imagine. He's brilliant, after all. A genius. Only…. I don't think he would. I mean, he'd want to; he'd really, really want to. Just…. He couldn't, not in good conscience. Sometimes meddling…isn't worth it. The consequences, I mean. Change something now, and look at the potential that's lost in the future. And with Sam—me," he hastily corrected. "Sorry, think I was tuning into the Doctor again. But with me, I can do so much on my leaps, changing so many things for the better. If the Doctor fixes the retrieval system, he might change all that."

"But wouldn't it just give you a chance to regulate your leaps? So that you aren't at it constantly?"

Sam opened his mouth but looked like he was reconsidering his answer. "Well—yes," he finally agreed. "Theoretically."

"Well, that's a good thing, isn't it?"

"Theoretically."

"Why wouldn't it be?"

Sam sighed. "It's just a feeling, that's all. But that fear doesn't override the longing to go home. You will. The Doctor will keep you safe, and he'll make sure you get home. He just…can't do the same for me."

"We can take you to visit, at least. In the TARDIS."

"I don't think that would be a very good idea," Sam said hastily. "Colliding timelines; too much of a risk of knotting them, gnarling them into something that shouldn't be. Because that…would take a while to sort out. Longer than this, even. And, frankly, after this last mess, I don't think I should take the chance."

"We could ask."

"Who can we ask?" Sam shook his head. "The Doctor's back at the Project, and he's not coming back until I leap out of here. You'd be hard pressed to find an exception to that." He stopped suddenly. "Unless…nah. But…no, would it?"

"What?"

He seemed to remember she was there. "Well, I thought Al might be able to talk him into helping us target my next leap, but I don't think he'd agree to that any more than he'd help us fix the retrieval system. If we sent someone else into the chamber, we could probably target it, but I'm already leaping."

"There's always a chance you'll figure it out eventually, isn't there?"

"Oh, of course there is, Martha Jones," he exclaimed, the forlorn look on his face fading away as he grinned at her. "And I expect I'll be betting on that." Martha was still frowning at him, so he added, "Besides, if you were going to try to take me back home, you'd have to find me, and when you found me, you'd have to take me out of whatever leap I was in, disrupting whatever I was there to do, and possibly ruining my chances of putting it right, compromising my ability to leap out. So it wouldn't work."

"You've given this some thought, haven't you?"

"Plenty." She knew that expression of the Doctor's. It was the one that meant he wasn't about to pursue the topic any more, no matter what she tried saying. They stood in silence for a few moments, and then Sam said, "I ought to go and see if I can contact Al again."

"And I should wait here?" Martha guessed.

"You wouldn't make any sense of one half of a conversation," he reminded her. "And I don't think I have time to repeat everything. Tell you what, though. If I find anything out, you'll be the first person I tell." He smiled at her and slipped out of the TARDIS before she could protest.

It was only once he was gone that she realized he'd distracted her from her earlier concerns.

Sam jumped when Al called out his name. He turned around, spotting both Al and the Doctor, the latter of whom grinned at him and waved. "Did you manage it?" Sam asked, trying to get used to the fact that the Doctor he saw as a hologram in front of him had never met him before. It helped that the Doctor was still clad in white, rather than the suit Sam now wore.

"Oh, piece of cake," the Doctor said, waving the idea away with his right hand—his left was clutching Al's to maintain visual contact. "But we don't really have time to discuss that, I think."

Sam looked at Al, who grudgingly agreed. "Ziggy still doesn't have enough information to project why you're here," he told Sam.

"What did she say?" Al looked distinctly uncomfortable now, and even the Doctor kept his mouth tightly shut. "Tell me," Sam prompted.

"She says that unless things change, you've got three point six hours."

"Three hours, thirty-six minutes," the Doctor added helpfully. "Well, thirty-three now."

"Three point six hours until what, exactly?" Sam read the look on Al's face. "Oh, no, you're not telling me—? How am I supposed to get out of this? What happens if I don't?"

"You will," Al told him. "We'll figure it out. That's what we're doing now."

"Sam," the Doctor began, "I need you to tell me what I've done on this end. I need to know what you've found out. I can't depend on Ziggy's readings, not for this."

"He wanted to talk to you about that," Sam said. "And a few other things, I expect. But are you certain you don't know why I leaped in here?"

"I don't like this any more than you." Al frowned as he looked at the handlink. "We're not even picking anything up anymore. What the hell did you do?" The last question was addressed to the Doctor, who looked suitably sheepish.

"It won't last," he said instead of explaining himself. "Once the visual's broken, you'll be able to collect readings again. But it's not as essential as you think, not with this leap. Everything Ziggy's been picking up has been skewed. I mean, look at this." The Doctor waved his free hand around them. "We're not even properly on the other parallel. That's why Sam's signal's so weak; he's being pulled through to ours. Hence the temporal interference you ran into before. Unless you'd care to explain where the TARDISes are?" Sam was silent, so the Doctor continued, "Exactly. Al, let me see the handlink."

"If you think I'm going to let you near—"

"Yes, I know, and I know the threats if I damage anything, and from you I'll guess that keelhauling is in the top ten, but I need to shift us back to the other parallel or I'm not going to be able to talk with myself." Balancing on one leg—apparently expecting Al to grab his ankle, which he did with a roll of his eyes—the Doctor snatched the handlink and began fiddling with it, hitting various sequences of buttons before wrenching a panel off the back and poking at the circuitry.

"Now, Sam," the Doctor started without looking away from whatever he was doing with the handlink, "have you happened to notice anything, well, markedly different in my behaviour? The me who's been with you, I mean." He looked up briefly. "How much have I been telling you, exactly?"

"You want to know what the effects are on him now that I've changed his timeline."

"Enough, I see," the Doctor noted, his eyes lingering on Sam's face. "Yes, has the splintering been showing any effects so far?"

"A bit," Sam admitted. "He looks ill, but I don't know anything beyond that."

"So no glimpses or—?" Sam was shaking his head, and the Doctor looked relieved. "Good, good. None of the cracks have split yet if he isn't pulling on my new knowledge. That's good. Really good, actually." He rubbed the back of his neck for a moment. "I thought it would be worse than that. Never been happier to be wrong in my life." He returned his attention the handlink, and, after a few more seconds, snapped the back panel back on and hit a few buttons on the front. His finger hovered above one last one and he grinned at them. "Ready? Might give us a bit of a jolt, could be a smidgen disorienting if you're not prepared. Allons-y!" He hit the button, and immediately he and Al began flickering in and out.

Sam saw Al yank the handlink out of the Doctor's hands—causing the Doctor to momentarily blink out of sight, until he regained his balance and reached for Al's hand again—and scrutinize it, frowning. Al's words were garbled, but he was clearly less than pleased. Still, as Sam looked around, he saw that he was back on the other parallel. He'd noticed the disappearance of the Doctor's ship the first time, when he'd been slipping in and out, but with everything else, he'd had to push it to the back of his mind; he hadn't thought asking the Doctor questions that didn't directly pertain to the situation would have been practical at that time.

Behind him, he heard a high-pitched whine pierce through the crackling conversation, and he saw the Doctor, sonic screwdriver in hand. "I made it, I see," he said as the holograms stabilized. He thumbed the device off before pocketing it.

The other Doctor was inspecting him carefully, his expression grim. "You didn't have to adjust your brainwave patterns."

"Nah," the second Doctor replied in a light voice. "Didn't need the headache." But his expression fell to match his counterpart's. He glanced at Al and then at Sam before focusing on his other self. "How long do we have?"

"I had to short one connection out," the Doctor admitted, "so I'd say seventeen minutes, tops. Probably fifteen seconds less."

"Right." The second Doctor frowned before turning back to Sam. "Martha's waiting in the TARDIS, expecting an update on whatever Al could tell you. Go, talk to her. Distract her. Make sure she doesn't come out to see me."

"But—"

"You can make your excuses and come back out after, but, trust me, when my companions are impatient, or worried, or curious, they tend to wander off, and I don't need her wandering out here now." Without waiting for Sam to say anything, he turned back to the other Doctor and started jabbering away in another language.

As Sam started to walk away, he could hear Al protesting. "Isn't this going to translate?" he complained, clearly recalling something the Doctor had said to him at some point—perhaps even something from the leap Sam couldn't really remember.

The Doctors cut their dialogue short. "No," one answered simply. "Sorry, but I seem to have a tendency to be rude in this regeneration." And then the conversation resumed, the two of them speaking so quickly that Sam was fairly sure the thread of the conversation would have been hard to follow even if it had been in English.

A/N: Well, things are getting a little bit worse, aren't they? But that's only to be expected; it's not going to get better on its own. And I'm sure the law of entropy could be worked into an explanation somehow, but I'm also sure that that's entirely unnecessary, so I'll simply thank anyone who takes the time to review.