"Priority prisoner for you, Doctor," said the voice on the other end of the line.
"Do you have to call them 'prisoners,' Sanjay?" the Doctor said. "Can't we call them, I don't know, 'guests' or 'visitors' or maybe even 'friends we haven't met yet'?"
"My orders are to keep an eye out for alien incursions, assume possible hostile intent, and to keep them under lock and key if necessary. 'Prisoners' covers it, don't you think?"
"I have got to talk to Pete about those orders."
"You do that. In the meantime, I'll keep rounding up unexpected … visitors."
"That's more like it, Sanjay. Now, what's this one like?"
"Looks human enough. James from the Sevens rang us, said a woman appeared out of nowhere while he was cleaning the taps – and before you say anything, he meant 'appeared.' Said he heard a popping noise and saw her appear a metre off the bar, then hit the floor. She got up, ordered a double MacAllen 17-year –"
"At least she's got good taste."
"But no money, or not any from Earth. James said her coins winked at him. That's when he rang us. Lawrence and Siobhan tried the gentle approach first, but she wasn't so interested in that. It took six of my people to bring her down, and that was after she blew a perfectly square hole in the wall."
The squareness gun. The Doctor remembered where he'd last seen that: wielded by a woman who'd died for him. This was either her doppelganger, or the woman hadn't met him yet, at least not in her own universe.
This had to be her doppelganger. It had to be.
And yet, his lone heart thumped loud and fast.
"Sanjay, can you send me a photo of her?"
"Doing it now, Doctor."
It was a standard Torchwood mugshot: head from front and both sides; full-length portrait; results of initial body scan, which indicated human with possible genetic anomalies. In the full-length shot, the woman blew the camera a kiss.
"Sanjay," he said, focusing on keeping his breathing even and unsuspicious, "I'll be down to speak with this one shortly. And Sanjay – you haven't rung Rose about her yet, have you?"
"No, I haven't. She was next on my list."
"Don't worry about it. I'll tell her myself. And in the meantime, if she wanders by, don't let her speak to the prisoner without me being there."
"This is most irregular, Doctor."
"I know, I know, and I'm sorry about that. But I may know this woman … and Rose doesn't, if you catch my meaning."
There was a short chuckle on the line. "I very much do. All right. I'll leave it to you for now. But not forever, yes? I have protocols to observe, and the director will have my head if I don't follow them."
"You let me deal with Pete," the Doctor said, and rang off.
And Rose, he thought.
* * *
"Seven hundred forty-two," she said.
"Seven hundred forty-two what?"
"Seven hundred forty-two dots in the upper right quadrant of the ceiling before you came to see me." River rose, sauntered over to the plexiglass window separating her from the Doctor. "Hello, Doctor. Lovely to meet you."
"You know my name."
"I certainly do." That knowing smile he remembered from the Library: captivating, infuriating, seductive.
She pulled a familiar blue diary from her jacket. "The guards thought this was just a book. They're right, of course, but they've no idea what kind of book it is. You're right here in my spotter's guide."
How had that stupid human heart of his gone so loud? This had never happened when he'd had two proper Time Lord hearts. "You can't – I'm not from …"
A soft chuckle. "You think I'm from this universe? No, sweetie, I'm as unique as you are."
He crossed his arms over his chest. "How did you get here, River?"
"I'd like to know that myself," she said. "And I'd also like to know how you know my name."
"Well," he said. "Spoilers."
* * *
His head snapped back with a rush of timeline fragments, most with faces he didn't recognise, except for the few he knew were his own, which occasionally fell into the first category as well. One in particular seemed quite taken with River: a floppy-haired youngster with a bow tie.
The vortex manipulator dropped to the desk with a thump, spinning briefly before wobbling to a stop. He was never supposed to see his own future, and even though the splinters currently burrowing into his head hardly formed a complete frame, they were more than enough to know that his suspicions about River back in the Library had been well-founded.
He did know her, not always as well as she'd said he did, but now and then in the roundabout nature of time travel relationships. He'd seen her in his previous incarnations, too, incarnations that hadn't had those memories before he'd been budded from his own hand.
And he and River, they were ... close. Close enough that that the thought of Rose's reaction to the news shivered through him like the polar wind.
He tried to shake it off and concentrate on the vortex manipulator. How had River broken through universes, anyway, and was that method reproducible? How would she travel back? Because surely she did find her way back, unless she'd miraculously survived her vaporisation in the core of the Library, and this was some future River … no, no, that couldn't be it, because she'd been surprised he recognised her, which meant she hadn't met his tenth self yet … unless she was lying, because she'd said she lied all the time … and quite frankly, the more he thought about how she'd deliberately and accidentally entangled herself with his timelines, the more even his half-Time Lord head hurt.
He aimed his sonic at the vortex manipulator's case, gently levitating its screws anticlockwise until the frame jiggled loose. One thing at a time; one simple, easy question: could he fix it? Probably, once he sorted out how this model worked; they were all of a piece, these little time-travel jalopies, and nowhere near as intricate as the sort of temporal equipment he'd been holding together with duct tape and sweet words for hundreds of years.
Had once held together. Hadn't been for 576.23 days, not that he was counting.
He put down the sonic and rubbed his eyes. It still stabbed at him, not having the TARDIS, like the dull throb of an old injury, healed over but never fully right again. She was somewhere on the other side of that supposedly unbreachable wall River had managed to breach anyway, not that whatever hole she'd punched through the Void was large enough for him to hear his ship's song. She was still further away than the most distant star.
Except here, in his hands, was the awl River had used to punch that hole; the tool he needed to repair so she could return. He'd once tuned a vortex manipulator to transport three people five billion years and as many miles to Earth, but could he do the same across universes?
And more to the point, should he?
Outside his window, the London skyline spread in a vanishing point towards the horizon. The sky was unusually blue today, though in the distance, he could see a smudge of grey, an afternoon thunderstorm approaching. If he left now, he could catch a flight before the storm hit: Hong Kong, Kiev, Islamabad, Cape Town. Close his eyes, spin about the terminal, walk to whichever counter his finger pointed to, slap down his passport and ask for a ticket for the next international flight anywhere. It was as close as he could get to randomness now.
Sometimes he took Rose. Sometimes he didn't. He'd taken short trips all the time while his companions slept, or when he'd been companionless, and occasionally needed to feel the scorching desert wind or the chill of an icy mountain for himself, another secret to lock away in his mind and share only when he had to.
Rose was less sympathetic about those needs than he'd hoped. He supposed she had a point: they had one limited human life to share together, and those words – "share" and "together" – mattered to both of them. But Heathrow still called.
The Doctor got up and drew the shade. The room dimmed, but he didn't need much light anyway. He picked up the sonic and got back to work.
* * *
"I don't think you need to bother with this one," the Doctor said. "She sounds harmless enough."
"You know we have to talk to anyone Sanjay's team brings in."
"Well, there's 'have to,' and there's 'have to,' isn't there? And this one seems more of a 'not worth it.' Trust me, I've spoken with her already."
"Oh, you have, have you?" Rose seated herself, crossed both arms and legs. "And what exactly did you learn from Miss Not Worth It?"
"She's just an archaeologist," the Doctor said weakly, shuffling papers on his desk that were either in the wrong order or about to be. "I'm sure she doesn't mean Earth any harm."
Rose leaned in towards him. "So, how do you know her?"
"What kind of a question is that?"
"So you don't know her?"
"I didn't say that."
She cocked an eyebrow at him. "Go on."
He smoothed down his paperwork and placed his palms flat on the desktop. "I only met her once. On the other side, that is. When I was him, you know, not me. She seemed to know me ... very well, but I didn't know her. Time travel, and all that." He took a breath. "I saw her die, Rose. She doesn't know that. She can't know that."
"You know I'd never tell her. But what do you mean, she knew you 'very well'?"
"That's the thing, Rose. I'd never met her before, but she knew things about me, things I've never told anyone else."
"Not even me?"
He tapped his fingers on the desk, an agitated rhythm. "No. Not even you. The sort of thing that I could only tell someone if things had got about as bad as they could possibly be, only much, much worse than that."
She laughed. "Worse than anything you and I have seen?"
"Yes," he said, and watched Rose's face fall. "Just leave it, Rose. Leave her. You'll only end up fighting anyway, and I hate the idea of the two of you fighting. I'm working out a way to get her home. I should be done soon, and then we can all forget about this."
"Fighting. With some woman I've never even met."
"Please, Rose. For me. Leave it."
She pushed back her chair, stood up, and sighed. "Maybe. I've got loads of paperwork this afternoon anyway."
"You're not getting out of things that easily, mister," she said, leaning in to kiss him on the forehead. "But we can talk about it later."
"Yes," he said, and his hands stilled. "Later, yes."
* * *
The case was largely hexayoonium tetraoxide, a fair substitute for the monoyoonium the Doctor preferred for his most sensitive time travel components, and one that indicated the person who'd modified the manipulator had reasonable expertise. Neither material was available on Earth, and the Doctor steadied his aim with the sonic, delicately unthreading ridged dowels and screws until he could examine the circuitry concealed within the device.
Three alligator clips, a small transformer, and a voided warranty later, the Doctor had the vortex manipulator's circuit board hooked up to a diagnostics app on his tablet. The app was in no way configured to deal with circuitry this advanced, at least by default, but what a genius could do with it was an entirely different matter. Subroutine after subroutine scrolled by on his screen, each no more interesting than any other – coordinate libraries, universal location system transponder code, temporal displacement tables, all the ordinary foundation layers of any decent time travel software – except for one routine, completely uncommented and staggered with irregular white space, whose primary function call was "fastReturnSwitch."
Each part of the function called a locator subroutine, which was then passed an extraordinarily long string of numbers and letters; the sort of effective but inefficient programming technique amateurs used when they didn't know how to create and store arrays elsewhere. But there were patterns, sequences that repeated from string to string, though sometimes with minor shifts, like a mutated gene. He drummed his fingers on the table and stared at the tablet, waiting for the pattern to shift into place.
It didn't, but even if it had been about to, the trilling of his office phone broke his concentration.
"Yes?" he snapped.
"Doctor, it's Sanjay. I think you should come down here."
"I'm a bit busy at the moment."
"So is Rose."
The Doctor sat straight up in his seat. "What?"
"I came back from break and she was here – Leo must have let her in while I was out. I don't know how long they've been talking, but Rose brought in a chair. I think she means to be here for some time."
"Oh, no, no, no, no, no. I'll be right there, Sanjay."
"I thought you might."
* * *
The black and white monitor on Sanjay's desk showed Rose, arms and legs crossed defensively, barely inches from the plexiglass barrier to River's cell.
"He didn't want me to talk to you," said Rose. "He said we'd just end up fighting."
"Over him, I suppose? That man and his ego. It just doesn't quit."
"Yeah, well, he's not wrong about this." Rose leaned forward in her chair. "Who are you, River?"
"Just a traveller with a taste for adventure, like you."
"That's not all you've got a taste for, is it?"
River smiled. "I must say, I never expected to add the metacrisis to my life list. But I never expected to end up in this universe in the first place, either."
The Doctor wiped his face with his hand. He'd been red-faced and warm when he arrived; now a chill settled at his spine. "Sanjay," he said, "why am I still on this side of the door and not the other one?"
"Just a moment." Sanjay swung away from his desk and over to a set of controls by the door, where he paused for a retina scan and then entered a seven-digit sequence. There was a set of low thumps and clicks, and the door slowly swung open. The Doctor bruised his shoulder slipping through.
"You shouldn't be here, River," he said. "That vortex manipulator of yours was leaking chronon particles. You're lucky it dropped you here instead of scattering your atoms halfway across the galaxy."
"I've always been a lucky woman," River said.
"Rose," the Doctor said tightly, "I thought I asked you not to speak with her."
"Gorgeous mystery woman shows up, you and she've got history you've never mentioned to me, and you think I'm going to ignore that?"
"'Gorgeous'? Why, thank you, dear," said River.
The Doctor rubbed his eyes. "I'm just trying to keep things as quiet and simple as possible until I can find River a way home."
"Quiet and simple," Rose said. "By telling me not to talk to her. Because that's going to work." A weary laugh. "Look, I'm just checking on her. Making sure she's not planning anything."
"If you'd like me to plan something," River called helpfully from her cell, "I've got loads of ideas about how to pass the time."
"Time to go, Rose," the Doctor said, sighing. He reached for her arm, and though she glared at him, she got up and pushed the chair aside.
"You and me, we're not done with this," she said to him.
"I'm certain of it," he said. "Unfortunately."
* * *
"You tell me everything right now," she said.
"Sit down, Rose. Please."
She paused, then flopped on the opposite side of the couch from him. "Okay?"
"Thank you," he said. He took a deep breath, and told her about the Library.
* * *
"Here's the thing, Rose," he said. "She knew my name – my real name, the one I was born with. My name is very powerful. I keep it hidden for a reason. The fewer people who know about it – and that includes you – the safer we are.
"So that's why I said before that things must have been as bad as they could possibly have been for me to tell her my name, and it's also how I know that I must trust her as much as I trust anyone. I'd tell you my name, too, if I had to. I want you to know that. There is no one in this world, not even her, that I would rather be with, and if we were in the kind of situation where I had to tell you my name to save the universe, I would do it without hesitation. You must believe me, Rose."
She exhaled slowly, rubbed her palms on her legs, unwound the coil she'd made of herself. "Yeah," she said. "I do."
"But it's not the only reason I know that I trust her. I had a sort of vision while working on her vortex manipulator. Got some fragments of past mes who must have met her, and some of a future me. Quite a lot of that future me, in fact."
"Really? What do you look like?"
"Older, then younger. Or younger, then older. I'm not sure which."
"Right, that's so helpful."
"Rose," he said, and he reached for her hand. She was at last ready to let him take it. "Rose, I think that future me is married to her."
Rose blinked at him, and her hand fell limp in his. "What?"
"It was hard to tell. I only saw the timelines for a moment, and they were especially tangled there. But I'm reasonably certain she and I are married." He stroked Rose's hand with his thumb, and waited for her to respond to his touch.
Nothing. And despite Rose's order to tell her everything, there were other fragments, much more naked ones, that she certainly didn't need to know about.
"But if I'm married to her, that doesn't mean I've forgotten about you. And that future me, I'm so, so certain that he could not love River now if you hadn't mended a sad, broken, big-eared man who needed you more than he could possibly say."
One of Rose's fingers twitched in his, bending across his palm. She tilted towards him, brushed his cheek with her thumb, and kissed him once, then again, drawing back with a swift tease of her tongue against his lower lip. "You were laying it on a bit thick there for a minute, but I'll take it."
"I lost you at 'big-eared,' didn't I?"
"Yeah, but that's okay. You really did have big ears back then."
He leaned in for another kiss, this one lingering enough for him to have time to wind his fingers in her hair. "So, I'm forgiven?"
"I'm working on it. But you don't ever get to tell me not to talk to someone because you think I'll go all stupid and jealous, yeah? Because if I do, that's my choice, not yours. Okay?"
"Okay," he said, relief pooling through him. "But Rose?"
"You were a bit jealous."
"Oh, shut up."
* * *
There was still no sign of customisations that would have allowed River to cross the Void. Even the mysterious fastReturnSwitch routine had none of the transform computations he'd expect might thin the barrier between universes; it was simply a switch, as its name suggested, looking for matches to the lengthy strings.
All those repetitive patterns, as if the strings represented items that were nearly, but not exactly, the same. Thirteen items; a baker's dozen, an unlucky number, the ancient regeneration limit ...
Of course it was.
Thirteen patterns, all similar, but with variations. Thirteen people, all similar, but with variations at the genetic and temporal level. One of which was him.
fastReturnSwitch was River's fail-safe: a way for the vortex manipulator to seek him out when River called it into action, as she must have before she'd apparated in the Sevens. It still didn't clear up how she'd punched through to Pete's World, but it at least explained why she'd turned up round the corner from his office building.
The rest, it seemed, he was going to have to get directly from her.
* * *
"Bare walls," she said. "Almost as if you're a man who doesn't plan on sticking around."
"I'm not the sort of man who needs motivational kitten posters. Not that there's anything wrong with motivation, or kittens, or motivation involving kittens, though in my experience, kittens aren't the best model for a well-organised and productive workforce. And you, River, are trying to distract me."
"Was I that obvious? I'll have to try harder next time."
"How did you do it? How did you get here?" He thrust the manipulator towards her, then snatched it back when she reached for it. "No. Not yet. Not until you tell me how you did it."
"Why? So you and Rose can go back? If it were that easy, you'd have done it already, even if it meant leaving me behind. Where is Rose, by the way? Shouldn't she be part of this little gathering?"
"She's in a meeting, but she'll be here soon." The Doctor replaced the manipulator on his desk, covered it with his hands, hiding it from River, and from himself. "I don't like mysteries I can't solve, River."
"Oh, sweetie." She sighed. "There's nothing to solve. It was an accident. I was trying to visit some old friends who live among a very tangled set of timelines, and something must have gone wrong."
"An accident. That's all?"
"As if you've never taken any accidental detours. Honestly, if you knew how to fly your ship properly –"
"I flew my ship just fine, thank you very much," he said, his heart tightening. His hands pressed on the vortex manipulator.
"Whatever you say, sweetie." That cocksure smile he remembered so well from the Library, even more frustrating now that he knew her attitude was borne of certainty, not bravado. "Now, if you don't mind, I believe you promised me my vortex manipulator once I told you how I got here."
The Doctor slapped it into her outstretched hand, and she clasped his in return. The memories he'd acquired from the vortex manipulator bubbled at the lowest levels of his brain. Memories of River holding his hand, even though it hadn't happened and would never happen in this body; memories he'd kept back from Rose, because they involved far more than hand-holding.
"You look like you have another question," River said.
"No. No, I don't. I really don't." He dropped back into his chair with a rough exhale of breath. "All right," he said. "Who are you to me, River? Because I saw things in that vortex manipulator. Images of your timeline with me. Things I don't remember even though I should. And don't give me that 'spoilers' nonsense; if I'm stuck here in this universe, what can I possibly do with your secrets?"
"You may not be stuck here forever," she said carefully. "And I say that because I know you, not because I know your future. But I'll give you one answer: when you had that nose and those ears? You alone at the bar, feeling sorry for yourself while Rose and Jack were on the dance floor? Us in that back room, with the handcuffs?" Smoke in her voice curled around each word. "I know it's a night I'll never forget."
He'd only had a second or two with that memory, but it was enough to redden his face. "Yes. That's the one."
River wrapped the manipulator around her wrist and tapped at the keys. "You don't remember because you asked me not to let you remember. Not in so many words, but close enough." She peered down at the display, pressed another button, and left her finger poised over the device. "Now, if you don't mind ..."
Rose swept through the doorway, a little blonde blur aimed straight for River.
"I do mind, thanks for asking," Rose said, grabbing River's bicep. "You and him back then? You tell me –"
River started at the unexpected contact, jarring her wrist. Jarring it right into her finger.
A flash of light starburst through the room, then winked in, and was gone before the Doctor could finish yelling at Rose and River to stop.
And now they were gone, too.