Jo Grant stepped into the laboratory used by U.N.I.T.’s scientific advisor and looked around for him. Unusually, he wasn’t busy at the worktable with some peculiar part from the TARDIS. There were several odd looking pieces of something laid out on the table, but she wasn’t going to risk touching them.

“Doctor?” she called out.

“In here,” came a muffled voice from inside the blue police telephone box in the corner of the room. Of course, if he wasn’t in the laboratory he would be in the TARDIS. Jo had never found The Doctor anywhere else first thing in the morning. He probably slept in the police box. She certainly didn’t think he had any kind of flat, and he didn’t bunk in with the men in the barracks.

“What’s cooking?” she asked brightly as she stepped over the threshold into a different dimension than the one outside the box. The marvel of that was still with her, even now, but she did her best not to show it in front of The Doctor.

“The TARDIS’s time circuits are ‘cooking’,” The Doctor replied good humouredly. “As magnanimous as it was of the Time Lord Council to give me back the use of the TARDIS, they didn’t provide any new parts. If I can get the circuits calibrated fully it might make the old girl more accurate.”

“That wouldn’t be a bad idea,” Jo agreed. “That last time when we stayed exactly where we are but saw U.N.I.T. headquarters in the Jurassic era, the dark ages and the twenty-fifth century before we got home was a little worrying. I thought we’d never get back to good old 1973.”

“Oh ye of little faith,” The Doctor told her with an avuncular smile. “The old girl always gets there in the end. You should know that by now.”

“The ‘old girl’ is overdue for her MOT test, though,” Jo reminded him.

“Her five billion light year service, anyway,” The Doctor replied.

“The Brigadier is looking for you, by the way. That’s why I’m here. There have been some ‘odd goings on’ around London.”

“Define ‘odd goings on’ a little more, if you please,” The Doctor told her.

“I can’t. You’ll have to ask The Brigadier,” Jo answered. “When I said ‘looking for you’, I think he meant you were to go to his office.”

“Certainly not,” The Doctor replied. “I am not at his beck and call like his uniformed lackeys. If he wants to speak to me he will have to come here.”

“He said something about being in ‘command of this establishment’ and expecting his orders to be obeyed by EVERYONE,” Jo countered. “Don’t shoot the messenger, please. If you ask me, you’re both as stubborn as each other.”

“I happen to be very busy,” The Doctor argued. “The Brigadier, Rassilon bless him, is no more than a glorified pencil pusher sitting in his office giving out orders willy nilly. He can come to me.”

The Doctor went on in that mode, decrying military attitudes. Jo glanced around and cleared her throat meaningfully.

She did it again.

“Doctor,” she said after a while. “The glorified pen pusher is at the door.”

“Thank you, Miss Grant,” The Brigadier said, stepping into the TARDIS. He smiled wryly at her and then frowned at The Doctor. “You accepted the post of scientific advisor. That DOES put you under my command even if you are still a civilian.”

The Doctor scowled at The Brigadier and pulled a pair of levers. The Brigadier stepped out of the TARDIS hurriedly. Jo wasn’t sure whether to follow him or not. She compromised by backing away from the console.

“Oh ye of little faith,” The Doctor chastised them both. “I’m just initialising the realignment of the Helmic Regulator. Anyone would think I was about to land us in a void dimension or something.”

“I wouldn’t rule anything out with this funny old crate,” The Brigadier answered as he stepped back inside.

Jo didn’t say anything. She wasn’t there. Instead a young woman in black jeans and a jacket covered in multi-coloured badges stared around in bewilderment.

“Oi, what’s going on?” she demanded. “Where’s the Professor and what happened to the TARDIS?”

“That’s three questions in one and I don’t have an answer to any of them,” The Doctor replied. “May I ask who you are and what happened to Jo?”

“I’m Ace and I’ve never heard of a bloke called Joe,” the young woman responded. “Who are you two when you’re at home?”

“That at least I CAN answer,” The Doctor replied. “I’m The Doctor, and this is Brigadier Alasdair Lethbridge-Stewart of U.N.I.T. You correctly identified the TARDIS. You may as well know that it is currently parked in U.N.I.T. headquarters, so unless we establish who you are he’s almost certainly going to have you arrested as a trespasser.”

“I’m in the TARDIS,” Ace pointed out. “I live here. Nobody’s arresting me for anything.”

“Ah, I see,” The Brigadier said. “Doctor, I believe this must be a travelling companion of yours from some future time. This is what I’ve been trying to tell you. We’ve had people disappearing all over Greater London – and other people turning up in their place. The BBC are complaining that half the cast of On The Buses have disappeared while a group of young people claiming to be ‘Eastenders’ are wandering around in confusion. Woolwich Barracks have lost a squad of infantrymen and what they got in return are carrying some very advanced weaponry. A chap called Boris something or other is claiming he’s the Mayor of London. I’m not so sure about him. Sounds more like a Russian spy. And… we’re keeping this quiet for now, to prevent panic, but the Prime Minister and the Leader of the Opposition are both gone, while two strange characters turned up at Westminster instead. We’re debriefing them, now, but frankly, I cannot imagine a future when even the Labour party would have a leader called ‘Ed’.

“Doesn’t sound as bad as when I left Earth,” Ace commented. “We’ve got Maggie Thatcher in No. 10.”

“Margaret Thatcher is Prime Minister in your future time?” The Brigadier exclaimed. “My word, how extraordinary.”

“That’s not the word most people use about her,” Ace commented.

“Yes, well,” The Doctor intervened. “Are we to assume that Jo and the other missing people from our time have somehow ended up in a later era? If that is the case, then I can be sure, at least, that Jo is safe with my future self, and if Britain still has a democratic system of parliament, I dare say the other people will be all right for the time being. We should try to find out what’s going on in the meantime. Did you say your name was Ace?”

“Yes.”

“Even stranger than ‘Ed’. What a future. I hope I’ll be retired by then.”

“You ARE,” Ace responded. “I remember you, now. Me and The Professor met up with you at….”

The Doctor pressed his finger over her lips.

“My dear young lady,” he said. “What we have here is a paradox, and to avoid any further confusion of the timeline we really must avoid learning too much about the future, especially our own future.”

“Yeah, ok,” Ace responded. “Look, if you’re The Professor… I mean The Doctor… whatever…. you ought to be able to do something about all of this. You could take me back in the TARDIS and pick up your man, this Joe.”

“Jo is a young lady,” The Brigadier said. “I’m not too sure about you, but….”

“The TARDIS isn’t going anywhere until I finish these calibrations,” The Doctor pointed out. “You may be stuck here for a while. I suggest you take over Jo’s role here. I dare say she’s doing the same with YOUR version of me.”

“Suits me. What does this Jo do for you?”

“Well, a cup of tea would be quite nice just now,” The Doctor suggested.

“I don’t think so,” Ace responded. “I did enough catering when I was a waitress on….” She paused. “Never mind that, it’s probably another paradox. But this IS the twentieth century. Get your own tea.”

“I’ll have refreshments brought to the lab,” The Brigadier compromised. “While I fill you in with what we know so far.”

The Doctor sighed and turned two more dials on the TARDIS console then followed The Brigadier out into the laboratory. Ace ran two steps to catch up with him. Both The Brigadier and The Doctor were at least a foot taller than her and fell into a long stride, but she wasn’t going to tag along behind them.

Jo was just as confused as Ace about what had happened, but at least she recognised the TARDIS, and The Doctor recognised her.

“My dear girl,” he said. “It has been so long. Are you all right?”

“I’m….” She wobbled dizzily and accepted the reassuring arm of the middle aged man who reached out to steady her. “I’m… a bit confused. What happened?”

“Something rather odd,” The Doctor replied. “My young friend Ace was standing there a moment ago, and now you’re here.”

“Are you…” Jo shook her head slowly. “I know he can change his appearance. That time with Omega, there were three. Are you another….”

“Yes, Jo, I’m The Doctor, in a later time than you know. We’re currently in geo-synchronous orbit over London, Earth, in early 2015, picking up some rather odd and infuriatingly random energy signals.”

“I see… I think. Goodness, 2015. I’ll be… really old.”

“I wouldn’t be so rude as to comment, but the last postcard I had you were having a lovely time. I shouldn’t say anything else in case it causes a paradox, of course.”

“Well, of course.” Jo smiled brightly. She was in a strange situation, but The Doctor was there, so it couldn’t be so bad. “Is the kitchen in the same place it used to be? I’ll go and make a cup of tea while you study your random energy readings.”

“That sounds like an excellent idea,” The Doctor answered. “Yes, exactly where it used to be, thank you.”

Jo headed for the inner door. The Doctor turned back to the console, frowning. He didn’t want to worry Jo, but anything capable of transporting her onto the TARDIS and Ace off it while they were in orbit was a matter of extreme concern.

A female sergeant brought the tea and biscuits to the laboratory where The Brigadier outlined the pattern of mysterious disappearances on a large map of London spread out on the workbench. Ace was quite sure that male sergeants wouldn’t be doing a task like that and said so.

“As a matter of fact, Sergeant Benton often fetches tea,” The Brigadier answered. “Among others of the non-commissioned ranks. I don’t have a designated aide-de-camp to do those things. U.N.I.T. is something of a stripped down regiment with every rank pitching in with whatever task is necessary, be it making tea or defending this planet from tentacled beasts from the Andromeda Galaxy.”

“There ARE no tentacled beasts in the Andromeda Galaxy,” The Doctor pointed out. “The Andromedans are a majestic people devoted to the fine arts and learning.”

“Can we please get to the point – women’s lib and the population of Andromeda have nothing at all to do with the sudden disappearance of people from this time and the arrival of others from another time.”

“Quite right, Brigadier,” The Doctor agreed. He turned to Ace. “Where – or more precisely, WHEN, were you with me when this happened?”

“We were in orbit over Earth,” Ace answered. “The Professor… I mean, you… said that it was the year 2015. You were monitoring some weird readings or something.”

“Alas, I have the TARDIS undergoing so many recalibrations that I have not been able to monitor anything,” The Doctor said. “The question, however, is an obvious one – do the energy readings originate in 2015, where my later self is monitoring them, or now, in 1973.”

“Does it matter?” The Brigadier asked a little impatiently.

“It matters a great deal. It would tell us whether the culprit is here in 1973 for you to deal with, or at the other end of this situation for your future replacement to act upon.”

“Ah, good point,” The Brigadier conceded. “So how do we find out if you can’t do anything to monitor the energy signals?”

“I can construct a portable device if you stop talking and leave me to it,” The Doctor replied, reaching for some of the strange parts on the table.

Ace sighed and grabbed a pencil and paper. She wrote a note, folded it over twice and wrote again on the outside of the fold. She showed it to The Doctor and The Brigadier.

“For the Professor, do not open until 2015,” The Brigadier read.

“To tell him to find out what we need to know – if the signal is from here or there… or now and then….”

“Excellent idea, Jo… I mean… Ace,” The Doctor said. “But I think we can employ more hi-tech methods of sending the message.”

He left the table and headed back into the TARDIS. Ace followed, wondering what he meant. She watched as he typed her message out on a keyboard.

“Now, my dear,” he said when he was done. “Please put your thumb on the screen, just there.”

Ace did as he said, placing her thumb firmly on the monitor screen below the text. She was surprised when her thumbprint appeared as a signature on the note. Even in the late 1980s when she learnt to use a computer they couldn’t do that, and this one looked far more antique than that.

“I’m now time-locking the message. My later counterpart will receive it a short time after you left the TARDIS.”

“Very clever. But how will he get a message BACK to you?” Ace asked.

Logically, of course, it was perfectly possible to leave a message in 1973 to be read in 2015. But the reverse was far more difficult.

The Doctor smiled and tapped his aquiline nose.

Jo brought the tea to this new Doctor who thanked her for her kindness.

“It’s all right, I do it all the time for you… in U.N.I.T. You remember, don’t you?”

“Yes, I do,” he answered. “And I remember taking it all for granted in an appalling way. The misogyny of the times rubbed off on me, I think.”

“You’re forgiven. Have you found out anything at all about what happened?”

“Only that your appearance and Ace’s disappearance weren’t coincidences. A number of very important people, and some less important ones who must have been mixed up in it all by mistake have been transported through time. Apparently Edward Heath has been stomping around No. 10 furiously. Among other things he doesn’t like the twenty-first century wallpaper in the lounge and the fact that the government is proposing a referendum on leaving the European Union.”

Jo smiled wryly. She hadn’t actually stepped out of the TARDIS in the year 2015, yet. She wasn’t sure she wanted to. It might be harder to get back where she belonged if she did.

“Doctor,” she said, seizing on a point that had been nagging at her for a little while. “If you remember me, and U.N.I.T., don’t you remember this happening… me disappearing like this?”

The Doctor looked at her as if she had said something very obvious that he had completely missed until now.

“I should remember, shouldn’t I,” he said. “When I try… I can recall some details… that very fetching dress that you’re wearing…. Yes, I remember that, and recalibrating the TARDIS, The Brigadier coming to tell me that something was amiss… but the rest of the memory is so woolly that I didn’t even think of it at all until you mentioned it.”

“The Time Lords took your memory of how the TARDIS worked,” Jo pointed out. “Perhaps this was their doing, too? Perhaps they felt you shouldn’t remember.”

“That is perfectly possible. After all, it DOES create something of a paradox. But it is a nuisance. If I had any memory of events in 1973 it would answer some of the questions I have.”

As he spoke, the TARDIS console beeped insistently. He looked around in surprise.

“It’s a communication,” he noted. “Who would be communicating with me?”

He looked and smiled warmly.

“Ace sent it. Her thumbprint is fixed to the note. There’s a postscript from myself, asking me to take care of you. That goes without saying, of course.”

“What does she say?” Jo asked.

“Find out WHEN the signals originate,” The Doctor answered. “Oh, yes, why didn’t I think of that? Or perhaps I did, but it was Ace who thought to ask.”

“It was the right question, then?” Jo queried.

“Oh, absolutely the right question. The signature of an incoming time warp and an outgoing one should be distinctly different. Yes, that’s the key to unravelling this mystery.”

He became very animated, pressing buttons, pulling levers all around the console. Jo wondered if there was anything she ought to be doing, but this version of the central TARDIS control was so very different to the one she knew she hardly dared touch it for fear of doing something terribly wrong.

“Doctor, there are people outside,” she pointed out. “Where did we land?”

“Inside U.N.I.T.’s twenty-first century headquarters at the Tower of London,” he answered. “That will be the equivalent of The Brigadier and his people come to ask for my help with their little dilemma. Open the door, would you, my dear, and invite them in.”

Back in 1973, The Doctor was constructing his portable device while waiting for a response from his later counterpart. He still hadn’t explained how that was going to happen, but he seemed certain it would. The Brigadier was making use of the laboratory phone to demand transport to bring all of the people who were out of their time to U.N.I.T. headquarters for a full debriefing.

“Not here,” The Doctor said, looking up. “Take them all to the Tower of London.”

“I beg your pardon,” The Brigadier responded. “These people include a future Prime Minister of great Britain and Northern Ireland, even if he does seem an odd chap. We’re not going to lock them in the Bloody Tower.”

“Not at all, Brigadier,” The Doctor replied. “In the twenty-first century U.N.I.T.’s main headquarters are in the Tower undercroft. Your counterpart in 2015 has brought all our missing people there. When I find a solution to the problem, it would be useful if everyone was in the same place.”

“You got a message?” Ace asked. “From the Professor… from you in the future? How?”

“Telepathy,” The Doctor replied. “Time Lords can directly communicate with each other over both space and time. I generally don’t as I have very little to say to them. Talking to myself is not actually recommended. Receiving the message gave me a terrible pain in my telepathic nerves.”

He rubbed the back of his neck and winced in physical proof of that, then prepared another message to send back by the less painful means of the TARDIS. He sent Ace to do it. When she returned he was rubbing his neck again.

“Another communication?”

“The one I needed,” he assured her. “The point of origin is in THIS time. Somebody from this present is projecting a signal into the future where you and your version of me were - which is causing this temporal displacement of people.”

“Can you trace this point of origin?” The Brigadier asked.

“I will be able to in about five minutes,” The Doctor replied. “If I don’t lose all my faculties through all this telepathic chit-chat.”

The Brigadier and Ace didn’t add to his problems. They had a private conversation of their own about The Doctor and how much trouble it was possible to get into just by knowing him. Neither of them revealed anything that might be considered a paradox, but they both agreed that their lives would be quieter, easier, but so much less interesting if they had never met the man The Brigadier knew as The Doctor and Ace as The Professor.

“Here we are,” he called out finally. “This will do the trick. Get ready.”

The Brigadier and Ace both thought ‘get ready’ ought to mean stand by the emergency exits and prepare to evacuate.

The device The Doctor set in motion, though, did nothing too terrible. A flange spun around at an alarming rate and it emitted a peculiar whirring sound before settling down to a high pitched whine. After a few minutes the spinning became a gentle rotation and finally came to a stop.

“I have a co-ordinate,” The Doctor told them. The point of origin for the signals is in Chelsea.”

“A rich alien?” The Brigadier remarked.

“Or a fashionable mad scientist,” Ace countered. “Could go either way.”

“We’ll find out when we get to the spot. Brigadier, the TARDIS would be much more use to me at the Tower of London where the victims are being mustered. Can you arrange for it to be taken there while we head for Chelsea?”

“What about me?” Ace asked. “I want to be in on it. Don’t shunt me off to the Tower to look after a bunch of deadhead politicians and some bloke called Boris.”

“It might be dangerous,” The Doctor pointed out. “Anyone capable of causing this sort of chaos might do anything to stop his plan from being thwarted.”

“I really don’t think you should….” The Brigadier began.

“I’ve taken out Daleks,” Ace responded. “Two of them. One with a bazooka and the other with a baseball bat.”

“Er….” The Brigadier began before the vision of this spirited young tomboy firing a bazooka at a Dalek firmly rooted itself in his mind. “Well… if you come with us, it is strictly as an observer. We’re certainly not going to issue you with a bazooka.”

“Spoilsport,” Ace responded, but she wasn’t being left out of the action. That was the important thing. She knew what the past was like for male chauvinism, especially within the military.

Jo made herself useful helping to provide refreshments for the two dozen worried and angry people who had been transported through time from 1973 and then brought to the Tower of London and asked to make themselves comfortable in what still looked suspiciously like a dungeon even with a coat of paint on the walls and carpets on the floor.

The Doctor, meanwhile, was in discussion with the U.N.I.T. people of this time who looked very different from the U.N.I.T. Jo knew. Mike Yates and Sergeant Benton were long retired. The Brigadier was dead. She had overheard somebody telling The Doctor that. Of course, he would have been very old, but it was sad to hear, all the same. She wondered how she would feel when she got back to her own time and saw him again.

There was a woman in charge. Her name was Kate Stewart. She smiled warmly at The Doctor and was a little in awe of him. She was The Brigadier’s daughter who wasn’t even born in 1973. The Doctor didn’t seem to mind complications like that, but Jo felt awkward talking to her, even though she was sure they could probably be huge friends if the circumstances had been different.

“Please be patient,” Jo told the Prime Minister as she handed him a cup of tea. He was fumbling with an empty pipe which he had been told he couldn’t smoke inside the building. Above all the other changes to the country since he was in power the workplace smoking ban seemed the most incredible to him.

“I must get back,” he pointed out, voicing his concerns to Jo in the absence of anyone else who wanted to listen to him. “There are important matters to be dealt with. The country will go to pieces without me.”

“The Prime Minister from this time is missing, too,” Jo told him. “But everything seems to be all right, so far. Besides, The Doctor is working hard to get you all back where you belong. You probably won’t even be missed.”

Mr Heath was surprised by the idea that he wouldn’t be missed if he was gone for a few hours. He tried to convince Jo that it was not the case, but The Doctor called her to him, and he trumped a Prime Minister as far as she was concerned.

“My younger self has some news,” he said. “Everything will be sorted out very soon.”

“Younger self?” Jo smiled. “Yes, I suppose he is, but if you were standing side by side….”

“Appearance and actual age are irrelevant to Time Lords. Ask The Brigadier. He knew me when I looked even older.”

“Anyway, I hope you’re right… both of you. The Prime Minister isn’t the only one who wants to go home. I heard what they call music now, and I don’t think I could fit in here at all.”

The U.N.I.T. force descended on the leafy avenue in the Borough of Kensington and Chelsea. It was five o’clock in the evening and all was quiet. The arrival of a convoy of Bedford lorries from which armed soldiers poured was something of a shock to everyone.

The house at the centre of all that activity was a tall, white-fronted slice of select London townhouse with bay windows on all three floors and steps leading up to the door. It was the sort of residence where stockbrokers and barristers would live, or at the most bohemian, perhaps a record producer or a successful artist. It really didn’t seem the likely home of either an alien bent on conquering Earth or a ‘mad scientist’ with ideas about world domination.

But The Brigadier had seen just about everything by now and he wasn’t taking any chances. His men covered the back of the house, too, before Sergeant Benton ordered the front door broken open with a battering ram and led the charge into the hallway.

By the time The Brigadier, The Doctor and Ace entered the premises it had been secured. Captain Yates told them that the suspect was in the basement. He showed them the way down a narrow set of steps to a room that other people in the neighbourhood might have used as a quiet study or a flat for a live-in housekeeper.

This man had made it into a science laboratory that outdid the facilities The Doctor had at U.N.I.T. headquarters. The computer array took up one whole wall, and on a desk in the middle of the floor, connected by a whole collection of cables and conduits, was something clearly handbuilt. It looked very much like the sort of contraption The Doctor himself would build.

The Doctor immediately went to examine the machine, and he was fulsome in his praise of the workmanship. So much so that The Brigadier began to get annoyed with him.

“Doctor, this may well be marvellous technology for a Human in this decade, but it is obviously illegal. Can you stop recommending this man for the Nobel Prize.”

“Oh, very illegal,” The Doctor confirmed. “Though not under any law passed at Westminster. This contravenes the very Laws of Time themselves. Do you know what my people would do if I told them of this experiment?”

The Doctor looked at the ‘mad scientist’ as he spoke. The man was surprisingly young and if Jo were there instead of Ace she might have thought him ‘dishy’. He was being held in his seat by two U.N.I.T. soldiers and had said nothing to incriminate himself.

He looked back at The Doctor and shuddered even before he told him how Time Lords punish those who break the Laws of Time.

“We have a prison called Shada, on a fragment of a planet held in orbit by technology beyond the imagination of humans. On Shada prisoners are put into individual cells just big enough to stand up in and they are cryogenically frozen until their sentences, usually no less than three thousand years, are complete.”

“You… can’t….” the scientist stammered. “I’m a… Br…British citizen. I… I… the Geneva Convention… you… can’t… do that to me.”

“Maybe he can, maybe he can’t,” The Brigadier said. “But U.N.I.T. have a prison, too. It’s a dark, miserable place where we put people who we want to be forgotten. So you’d better start explaining yourself, fast, sonny.”

“I… I have a wife,” he said. “And a baby daughter. They’re… in the country at the moment, with her family. I did it for them… for my little girl, so that she would have a future….”

“You mean this was about money?” The Brigadier responded angrily. “You were going to blackmail the government?”

“No, not at all. I have money. I’m… My name is Jonathon Carlisle. My father is Lord Carlisle of Farnborough. I mean a FUTURE. This world is in chaos. Nuclear oblivion is only a step away every day. I wanted the politicians and others to see what their actions now would do to the world…. I sent them into the twenty-first century to see the devastation.”

“What devastation?” Ace asked. “You stupid chump. I come from the nineteen-eighties. There was no nuclear war then. I’ve seen the nineties and the start of the twenty-first century. There’s trouble in the same parts of the world you have trouble in now, but nobody has used nukes.”

“You might have had a little faith in your fellow man,” The Doctor told him. “Nobody wants that kind of thing. Your generation and those that came after all worked towards disarmament. They strove to prevent what they knew they could do to each other. They didn’t NEED your interference.”

“It all went wrong, anyway,” Professor Carlisle admitted. He pointed to his machine which The Doctor was still examining carefully. “There were reverberations from the time holes. If I use it again, it might….”

“Rip apart time and space and bring upon a cataclysm that would reach much further than a mere planetary nuclear war,” The Doctor said. “Time would cease to exist. Your daughter would be born a million times and die in the same instance along with The Human race and countless races across the cosmos.”

“Blimey,” Ace commented. “Really? All from this get up in a cellar in Chelsea?”

“Really,” The Doctor insisted. “That’s what comes of meddling with matters you don’t understand. Brigadier, would you please pull that plug over there – the one connected to the mains electricity.”

The Brigadier pulled it. The computers all died. The machine on the table gave out a kind of groaning sound before it, too, went quite dead.

“What?” Ace was surprised. “All it took to put a stop to him was to pull out the power cable?”

“The most complicated problems often have simple solutions,” The Doctor replied. “Brigadier, your people will need to dismantle all of this equipment and have it taken to secure storage. It must not be re-assembled. As for him….” He glared at the professor. “His intentions were honourable. But he was a fool. You may decide for yourself what his punishment should be. Perhaps Parliament might bring in a special ‘Extreme Stupidity Act’ especially for him.

“The Prevention of Gormless Idiots Act,” Ace suggested. “Just one problem. The Prime Minister is in 2015, according to you, and it doesn’t look like we can use this gismo to get him back.”

“No,” The Doctor admitted. “We’re going to have to sort that one out ourselves.”

By ‘ourselves’ The Doctor really meant, by himself – or perhaps himselves if there was such a pronoun. Back at the Tower of London, where Professor Carlisle was brought in U.N.I.T. custody, though not to the Bloody Tower, The Doctor immediately sent a message by TARDIS and received a telepathic reply that caused him to yelp in pain.

“That ought to be the last one,” he said. “Good job, too, or I would end up with a terrible migraine.”

As it was, he sat down quietly and waited for events to resolve themselves around him. His head was spinning and he really would have liked to lie down in a dark place.

A few minutes later, another TARDIS materialised next to his. it looked very slightly different. The roof was flatter and the paintwork was fresher. The chameleon circuit had updated the appearance just a little.

The Doctor waved to his later incarnation as he stepped out of the new TARDIS followed by the politicians, actors and military people who had been taken out of their proper time. Jo came last, running to greet him enthusiastically.

“Yes, I’ve missed you, my dear Jo,” he said to her. “But I do have a dreadful headache. Can you tell me everything a little more quietly.”

The people from the twenty-first century got into the TARDIS in exchange for their 1973 counterparts. The Brigadier gave a sigh of relief. He still wasn’t sure about that one called Boris. Funny sort of Londoner altogether, but he was somebody else’s problem in the future.

Ace said goodbye to The Doctor in quiet tones before stepping into the TARDIS with ‘The Professor’. The TARDIS dematerialised.

“I meant to ask her WHY she calls me Professor,” The Doctor said, and then fainted. Jo was alarmed, but the U.N.I.T. medic who had been on standby in case any of the accidental time travellers had any problems confirmed that there was nothing seriously amiss.

“We’ll make him comfortable while I get this little lot debriefed and back where they belong,” The Brigadier said. “I dare say he’ll be well enough by the time we head back to The Priory. By the way, I’ve been having a chat with somebody about what to do with Professor Carlisle. He is rather a bright chap, and putting him in prison might be a waste. There’s an independent lot called Torchwood, a bit ad hoc at times, not as well organised as U.N.I.T., but they could use a clever scientific type. We’ll probably make him sign the Official Secrets Act and give him over to them.”

“Really?” Jo was surprised. “You’re not usually so kind to people who cause so much trouble.”

“His father has friends in high places. He might cause even more trouble if we just incarcerate him. Especially since there’s no chance of a trial. Besides, his wife and daughter might be happier this way.”

The mention of a daughter reminded Jo of something. She wondered if she ought to tell The Brigadier about Kate. He would be proud of her, of course. But since she hadn’t been born yet, it would surely be the kind of paradox The Doctor had warned her about.

“You’re a softie at heart, Brigadier,” she told him.

“Don’t let any of the men know,” he replied.

“Torchwood?” The Doctor said the word that had been mentioned just once a few minutes ago as he came around. “What have they been up to now?”

“Nothing,” The Brigadier answered. “How are you feeling now, old chap?”

“I’m fine,” he answered. “But… why are we in a dungeon? And is that the Prime Minister over there? Ask him to talk a bit more quietly, would you? I have a thumping headache.”

“You don’t remember anything?” Jo asked.

“Not since we were in the TARDIS and The Brigadier was demanding my presence in his office.”

“Ah!” Jo nodded in understanding. All that telepathic conversation had caused a bit of amnesia. That was why the later version of him didn’t remember her disappearing or anything else that happened. “Well, never mind. It’s all over now. Let me bring you a nice cup of tea while The Brigadier finishes off here, then we’re all heading back to Headquarters. You can have a proper lie down there while you’re waiting for the whatever it was to finish calibrating in the TARDIS.”

The Doctor was worried about missing out on what had obviously been some kind of national crisis, but the promise of a cup of tea and a lie down actually sounded very welcome just now.

“Just one thing… why do I have the name ‘Boris’ on the tip of my tongue? Who on Earth is that?”

“I have no idea,” The Brigadier said. “Sounds like a Russian, to me.”