Sometimes the TARDIS got confused. She was getting on a bit, after all, and she had been through a lot recently. She had to constantly calculate and navigate eleven-dimensional space-time. No wonder she made the odd mistake, put the wrong room in the wrong place at the wrong time.
It wasn't just that she didn't like Clara.
At least, so the Doctor hoped.
()
The first thing he had to do was make a phone call. A personal phone call of the most personal kind. He worked out what the extension number would be, and called the TARDIS.
"Come on," he said, as it rang out, "answer your phone."
"Hi, this is the Doctor, I'm a bit busy right now, so if you could leave a message that'd be brilliant. Unless you're the Terrible Zodin or Iris Wildthyme, in which case I don't know who the Doctor is and this certainly isn't his phone number. Anyway, message, beep, thanks."
The Doctor swore, hung up, and redialled. This time he got an answer.
"Hello," said the voice on the other end, "is that me, by any chance?"
"Yes," said the Doctor to himself. "Do you have Clara there?"
"Hang on... What's your name, sweetheart?" There was a brief pause. "Yes. Do you have Donna?"
The Doctor almost dropped the phone. "Um," he said, "I'll go and check. I'll call you back."
()
He was not running down the corridor to look for her. He was merely walking, albeit perhaps a bit quickly. Had he been running it would probably have hurt more when he turned a corner and fell over Donna Noble.
"Donna!" he exclaimed.
"Who are the bloody hell are you and how do you know my name?"
The Doctor ignored her questions, grabbed hold of her and drew her into a hug. Donna pulled away, shrieking and flapping her arms at him.
Then, of course, she slapped him. Hard.
()
"How come you can phone yourself? Why don't you just get an engaged tone?"
The Doctor looked to where Clara sat on the crash-seat. "Extension numbers," he said. "I change the code every now and then so I can call myself in an emergency."
"But if you're phoning through time -"
"I promise it makes sense to Time Lords. Now," he said, "rule one is don't tell me anything about my own future."
Clara waited for him to continue, putting on an expectant face. After a pause she asked "What are the other rules?"
"Haven't decided yet. Rule one is the important one, though. Nothing about my future."
"Okay," said Clara, doubtless immediately thinking of dozens of things she wanted to say to him.
"Will I be pretty, will I be rich?" he sang, trying to lighten the mood a bit.
"Who's Donna?"
"Friend of mine. We travel together." The phone rang before he could add anything to that. He picked it up. "Hello, me... Good." He breathed a sigh of relief. "Yeah, I've still got your one."
"'Your one'?" asked Clara, sounding offended.
The Doctor thought for a moment, then asked himself "Do you think we could route the phone line through the scanner?" He flicked a few switches with his free hand, switched on his webcam and waited in front of the scanner screen.
A monochrome picture faded in from black. There was quite a bit of interference,like watching the BBC in the Highlands in 1986, but contact had been made. He peered at himself in his own future. "Are you wearing a bow-tie?" he asked, incredulous.
"They're cool," said his future self defensively. "One day you'll come to appreciate that. Now, can we get this companion-swapping business sorted out?"
The Doctor scratched the back of his neck. He didn't really want to admit that he didn't know what was happening, but if you couldn't admit ignorance to yourself then who could you admit it to? "Your guess is as good as mine. I think we should hold off a bit on acting rashly until we know what's happened."
"Agreed," said the other Doctor.
"I'll investigate a bit and call again when I've got something."
"I'm sure you'll come up with something, I'm very clever." The other Doctor hung up the connection with a quick wave at the camera.
()
The Doctor took Donna with him to the fault locator room. It was a large, old-fashioned-looking machine which would send steampunks into paroxysms and it wasn't always accurate. Still, it was worth a try.
"What happens if there's a fault in the fault locator?" asked Donna, getting right to the question that everyone asked eventually.
"Then it takes a lot longer to work out what's wrong," he said.
She had another, more troubling question. "If this is the future then where am I?"
"Donna," he said carefully, waiting for the machine to power itself up, "this is quite some time after I met you."
"How much time?"
"Centuries," he said, letting her draw the wrong conclusion. He fought down the urge to tell her everything and warn her to stay away from... well, him, really. It was all his fault, after all.
"Oh," she said. She looked disturbed for a moment and then shrugged. "I never expected to live forever."
The Doctor decided that it was best not to reply to that. He waited for the fault locator to produce a printout of the current problems. It took a minute at most, but it was a fairly awkward minute, punctuated by the tapping of Donna's shoes.
"Well?" prompted Donna as he read the printout. "What's wrong with the TARDIS?"
"Nothing," he said, reading.
"Isn't that good? Oh, hang on, there can't be nothing wrong or it wouldn't be stuck as a blue box."
"Precisely." He was relieved that they seemed to have left the subject of her mortality.
"So that was a complete waste of time," said Donna.
"At least we learned that the fault locator isn't working."
"Bloody lot of use that is."
They left the room and stepped out into the wrong corridor. It was green and organic-looking and the Doctor instantly recognised it as the old coral desktop theme.
"This is like my TARDIS," said Donna. "I mean your TARDIS. I mean the other you."
The Doctor touched a wall cautiously, followed the corridor round a corner where it reverted to the usual hexagon theme.
"Oh, this is bad," he said, more to himself than to Donna. "This is whole new levels of bad."
()
The Doctor picked the phone up on the first ring. "What have you found?" He listened as his other self reported what had happened with the corridor.
"Where were you two going when all this started?" he asked when the explanation was complete.
"1969," said Clara, "to see the -"
"Moon landings," finished the Doctor. He looked to the screen and his fuzzy other self. "That's where we were going as well." They both knew what must have happened.
Clara was the first of the humans to work it out. "Did you crash into yourself?"
"Same time, same place," said the Doctor. "But there's a fail-safe in the TARDIS that should stop that happening. The central core won't compute the same eleven-dimensional materialisation-point twice. It can't. This stuff that's happening is completely impossible."
"What stuff?" asked Donna tartly, annoyed at being left out. "Can one of you tell me in small English words what's going on?"
"The TARDIS is merging with itself," explained the Doctor she was with. "We told it to occupy a specific point and it's determined to do it. We'll end up with one TARDIS made from two copies of itself."
She didn't immediately leap to the worst possible outcome. "So you'll have to share?"
"Donna," said her own Doctor on the scanner screen, "it won't be stable. As soon as it tried to leave the vortex... boom."
"Boom?"
"Boooom!" he moved his hands to give the impression of something exploding.
"Oh."
()
The TARDIS knew that something was wrong, something that would put both her and her passengers in danger. It was time to ring the cloister bell.
But which cloister bell?
()
"I'm sure you'll work something out," said Donna optimistically. "There's two of you, so that means you're twice as clever as you usually are. Not that I like stroking your ego, but I think you need a bit of encouragement."
"I wish I hadn't thrown the manual into a supernova," said the Doctor more to himself than to her.
"What did you do that for?" asked Donna.
"It wasn't very good - didn't really cover things that can't possibly happen." He gestured vaguely around himself.
"You're always saying things are impossible, usually when they're happening right in front of you. It has to be possible, because it's happened."
"Not necessarily."
Donna crossed her arms, unconvinced. "Now you're just talking nonsense to cover the fact that you use a word wrong all the time."
"No," he said, "I'm trying to distract you from the fact that we're probably going to die."
"Oh," said Donna.
"Which obviously isn't going to work any more now that I've told you." He had never been very good at lying to Donna, who tended to batter her way through to the truth by sheer force of personality.
"We've been in worse situations than this," said Donna.
"Actually, no. This is about as bad as it gets. We'll die, the TARDIS will die, and a large section of the universe will be rendered uninhabitable."
Donna thought this over. "Well then, you'd better come up with something quick-sharp."
()
Back on the other TARDIS (which was the same TARDIS and in the process of eating itself), the other Doctor (who was also the same Doctor) was explaining the situation to Clara. He could tell that she wasn't quite following his technobabble, but he kept talking anyway.
"When the central cores fuse there won't be any way to separate them," he said. "We need two control rooms to have any chance of forcing them apart."
Clara nodded, so either she did understand or she was just used to him talking nonsense.
She seemed nice enough, but the Doctor was avoiding non-technical topics of conversation in case she accidentally told him too much. He couldn't shake the feeling that there was something almost obscene about knowing about one's personal future. As it was he was going to have to dress like a hipster and wear a bow-tie.
"Seriously? A bow-tie? Am I wearing that for a dare?"
"No idea," said Clara, "you had that on when I met you. I always just assumed it was ironic in some way."
The Doctor scratched at his chin. "I've always had such a good sense of style. Well, I say always. Most of the time." He shook his head to clear it. "I need to focus. We should be safe enough for now as long as we stay in the vortex," he added, trying to reassure his other self's companion.
()
The TARDIS felt something break inside herself. This would be a good time for that cloister bell, but she was certain that her Thief had noticed by now that something was wrong. He was fairly observant, after all.
()
"When the central cores fuse there wont be any way to-" the Doctor stopped. "Hasn't this already happened?"
"Deja vu?" suggested Clara, looking worried.
"Time Lords don't get that," said the Doctor, consulting the internal clocks and his own sense of temporal location. "Humans only get deja vu because your sense of time is rubbish."
"Thanks."
"The engines must be starting to leak," he said, mostly to himself. He opened the connection to the other TARDIS. "I'm getting some repeats here," he said. "Time's going all..."
"Twisty-wisty?" his future self suggested.
"'Twisty-wisty'?" he repeated, appalled at himself. Yes, he'd said timey-wimey on occasion, but he'd done so with a sense of irony and because he wasn't sure what other words to use.
"It's accurate," protested the man who was wearing a bow-tie on purpose.
"Boys..." said Donna in a warning tone.
The Doctor reined in his instinct to try and make himself look good by insulting his other versions "Well, we have to get a move on, whatever you want to call it."
The other Doctor nodded. "I've been thinking about a simultaneous rematerialisation. I know it's a bit tricky -"
"Tricky? We'd have to time it to the nanosecond." He thought for a moment. "It might work though." He moved around the console flicking switches and pressing buttons. "Obviously we'll have to control the materialisation manually."
"Obviously."
Clara broke into the flow of words. "Is this whatever-it-is going to work?"
"Yes," said the Doctors in unison.
"Are you lying to me?"
"It might," said her Doctor after a moment. "It should. If we're good enough at flying a TARDIS to the second and the centimetre."
"Can't you use the autopilot?" asked Clara.
"What autopilot?" asked the Doctors together.
The Doctor gently moved Clara out of the way to get at the controls next to her. "You might want to sit in the crash-seat," he told her.
"Will that be any safer?" she asked, doubtful.
Clearly this girl knew him far too well. He wasn't sure whether he liked that or not. He didn't mind when Donna showed terrifying insight, so maybe that was what had appealed to his other self about her. "Not as such. You'd still be smeared across space-time and then exploded into tiny little pieces."
"Right," said Clara.
()
"Is there anything I can do to help?" asked Donna as she watched the Doctor work.
"No. Yes! Cross your fingers."
Donna didn't. "I'm not stupid, you know."
"I didn't say you were," he said, trying to concentrate and refusing to get distracted worrying about Donna's self-esteem issues at a time like this. "On the count of three," he said.
"On three or after three?" asked the other Doctor.
He glared at himself. "I said on three."
"Just checking."
"Right. One... two... three!"
()
The TARDIS shrieked mechanically as she began to slip from the vortex. The floors shook and the walls started to vibrate. Clara fell off the crash-seat with a startled yell.
The Doctor glanced over at her, but he couldn't do anything to help in any case. He took off the handbrake and slammed the stabilisers to neutral.
The time-rotor in the centre stopped and started fitfully.
"It's not working!" he yelled to himself over the scanner. "She's going to shake herself to pieces!"
"We've got to try! Just keep her under control!"
The TARDIS hit the 1980s and bounced off a black hole. She missed 1969 completely, tumbling through the centuries like a runaway train.
"I'm going to abort," said the Doctor, shaking his head. He pulled the brake lever, dragged his time-machine back into the relative safety of the vortex. The TARDIS shuddered once and then stopped.
"Are you okay?" he asked Clara.
"Yeah," she said. "Just landed a bit funny." She rubbed her arm.
The Doctor stepped round the console to check her over. "Nothing broken," he said when he had scanned her with the sonic screwdriver. "Just a few bruises." He felt a certain fondness for her already, and was fairly satisfied that he wouldn't lose his knack for picking out people to travel with.
The phone rang.
The Doctor picked it up, fussing with the scanner as he did so.
"Sorry," said his future self, "lost the connection at this end. I'm trying to fix it."
"How's Donna?" he asked. He'd been trying not to worry, and not entirely succeeding.
"Fine, don't worry about her."
"I can speak for myself, shoeface," she protested. The Doctor was relieved to hear her voice, and pleased that she still had her inimitable way with words.
"How's Clara?" asked shoeface.
The Doctor glanced over at her. "Sore arm but otherwise okay. Anything else I should know about?"
"I broke the blue stabilisers. Wait, you don't have those yet, do you? Okay, don't worry about those."
The Doctor made a face. "Anything that isn't a spoiler?"
"No, we're good."
()
Donna held a torch for the Doctor as he worked under the console. "What's next?" she asked. "What's the plan?"
The Doctor took the torch from her and sat up. "We don't have many options," he said quietly.
"You're not just giving up, though."
He stood up and dialled the past, handed the phone to Donna. "Probably best if you ask him,"
"Doctor, what's going on?"
There was a pause before he answered. "In the circumstances, the best we can do is try to limit the damage. We might be able to reduce the amount of space-time that gets destroyed in the explosion."
"What does that mean?" she demanded.
Another pause. "Donna, we're going to have to use the self-destruct."
Donna stared at the phone in her hand. Then she said, "No, there's got to be something else."
"Tried everything else," said the other Doctor, taking the phone from her to discuss the details.
Donna sat down heavily. The Doctor felt terrible. He didn't mind dying himself if would save other lives, but Donna and Clara didn't deserve to die like this, all because he'd got careless about revisiting the same places.
"I'm sorry," said the Doctor after a while. "I wish I was here to tell you how great you are and how much I like you."
"Stop trying to blind me with pronouns," she said.
He touched her cheek gently, hoping she wouldn't hit him again. He wanted to tell her that everything would be okay, that she didn't have to die here and now. He wanted a lot of things. "You were one of the best," he said, kissing her forehead.
()
"Wait!" cried Clara, grabbing the Doctor's arm.
"I'm sorry," he said, "but there's no other option." He tried to move her hand but she had a surprisingly strong grip.
"Why don't we do that thing where you talk at me and then you think of something and tell me how brilliant I am for accidentally inspiring you?"
He blinked at her. "What?"
"Would you rather just blow us all up and never know if there was something else you could have done?"
That didn't make sense, and yet it did. He looked at the scanner. "Doctor, what do you think? Waste of time?"
"Always waste time when you don't have any," said the other Doctor.
"Okay," said Clara, "talk at me, boys."
He nodded and started describing the situation. "We've got two of the same TARDIS merging together, the result of a dodgy materialisation."
"And they won't separate," his other self added. "Donna, any stupid suggestions?" he asked, hopefully.
"Why don't you use a magnet?"
"That's a ridiculous idea," said Donna's Doctor. He liked it when she had ideas like that, they were usually helpful. "What's like a magnet for a TARDIS?"
"Opposites attract," said Donna.
"Like attracts like," said Clara at the same time.
"Why is a mouse when it spins?" asked the other Doctor.
Oh hand about... "What if we spun the internal dimensions?" he asked, making little circles in the air with his index finger and then putting on the clever-specs because every little helped.
"Centrifugal force in eleven dimensions at once? Outside normal space-time and without collapsing the pocket-universe?"
"What are you going to do?" asked Clara, looking bewildered but exhilarated.
The Doctor looked at her with mad eyes as he worked at the controls. "What happens when you spin a mass that isn't actually there?"
"I don't know."
"Neither do I!" He hit a big green button on the console.
()
He leaned over Clara as she started to return to consciousness.
"I'm not dead, am I?" she asked as she opened her eyes.
"You're alive and well," he said, smiling. He helped her to her feet.
"What about the others?"
"Fine," he told her, "they're fine. All back to normal."
"I suppose we can't go and see the Moon landings?"
He shook his head. "Too much interference there now. Luckily I've seen them live about... fifty times?"
"Better than being dead," said Clara.
"That was a close one," he agreed. "I really should look into fixing that fail-safe."
"Might be an idea. I'll put the kettle on." She leaned on the railing. "By the way..."
"If it's about the bow-tie..." he said warningly.
"Never mind," she said, smiling. "It's not important."
"Good," he said. He shook his head as he watched her go. "Bow-ties are cool," he said to the universe in general. "Wearing trainers with a suit, on the other hand..."