Battles in Time It's not just the Time War in which time and the ability to time travel is used as a terrible weapon. Here are some examples...

The War Games (1969) Using technology purloined from the Time Lords, an alien race kidnaps soldiers from different wars in Earth's history as part of a scheme to build an army for conquering the galaxy.

Pyramids of Mars (1975) The Doctor moves the threshold of an Osiran time-s.p.a.ce tunnel into the far future to age the evil 'G.o.d' Sutekh, caught inside it, to death.

City of Death (1979) Having accidentally been splintered in time throughout Earth's history, Scaroth of the Jagaroth devotes himself to advancing human civilisation to a point where he can build a time machine and go back and stop that accident but that would stop life on Earth from ever having existed.

Mawdryn Undead (1983) Contaminated by the sickly alien Mawdryn, the Doctor's companions Nyssa and Tegan can't travel through time in the TARDIS without making their condition worse.

Timelash (1985) Rebels on the planet Karfel are thrown into the Timelash a kind of wormhole that dumps them in twelfth-century Scotland. (Is that really a punishment?) Father's Day (2005) Rose changes history and exposes Earth to an attack by Reapers who are drawn to accidents in time like bacteria to a wound.

Blink (2007) The Weeping Angels feed off lost futures, sending you into the past and then consuming the potential of all the days you might have had.

'I'm not saying folk round here are suggestible,' said Miss Perpugilliam Brown, the American with the extremely large dowry, to her aristocratic English fiance, Lord Roderick Pottinger, 'but in the park I saw eight men with orange spats, three with polka-dot cravats, and one poor man had even gone to the trouble of putting teddy bear b.u.t.tons on his waistcoat, even though teddy bears won't be invented for another hundred years.'

Lord Roderick guffawed (there was really no other word for the sounds coming out of his mouth). Peri tried not to wince. 'Dem it, could listen to you babbling nonsense all day, gel,' the man boomed before leaving the room, probably to go and hunt a fox or shoot a pheasant.

'If I get married,' Peri said to the painting above the mantelpiece, 'it's gonna be to someone quiet. Someone who never shouts or shoots or hunts or fights.' She sighed. 'I think maybe I'll just not get married. Ever.'

'The ingrat.i.tude!' That was the Doctor, the other shouty man in her life and the originator of the suddenly fashionable spats-cravat-waistcoat look (at least he tall, imposing, curly and blond of hair and determined of expression had the figure to carry it off, unlike most of the Regency spindleshanks). He had entered the room as she spoke and now stood beside her, also gazing up at the painting. 'After all the work it took to get Lord Roderick to propose to an elderly spinster such as yourself.'

'Yeah, thanks for that,' said Peri.

'Well, 21 is practically decrepit in the Regency marriage market.'

'I think I could've been 91 and it wouldn't have bothered him, with all the stuff you were spreading around about my dowry of millions.' She shook her head. 'No, I'm being unfair. He's OK. Better than his sister, anyway. It's just he's so... loud.'

They stood together for a few moments, Peri enjoying the blissful silence. But in the end, it was she who broke it. 'It's hard to believe such a beautiful picture came from something so evil,' she said.

If she hadn't known its background, the painting would have made her feel happy. Calm. Peaceful. It was a full-length study of a ballerina, something in the manner of Degas ('Edgar Degas, born in Paris, 1834, a founder of the Impressionist movement although he had little time for his fellow Impressionists and preferred to call himself a "Realist",' said the Doctor. 'That's not really relevant, though, is it?' said Peri. 'You're just showing off.'), its colours muted but perfect, the grace of the dancer singing from every brushstroke.

'Painted by an "Old Master" who at one point could barely manage a potato print,' said the Doctor.

'Do they have potatoes here yet?' Peri wondered, temporarily side-tracked.

The Doctor held up a hand and left the room. A few seconds later he reappeared and tutted. 'And you a botanist! Potatoes were brought to Europe from Peru by Spanish Conquistadors in the 1530s. Sir Walter Raleigh introduced them to Ireland fifty years later, and by the end of the sixteenth century they had spread throughout Europe, including England. So yes, by 1812 potatoes have been here for over a hundred years.'

'How come you know so much trivia?'

'Advantages of a large brain, Peri!'

'Which explains why you've got such a big head...' But she mumbled that one under her breath, and even though she was fairly sure the Doctor heard it he pretended not to. She decided it'd be best to go back to the subject of the painting. 'I wonder how Lord Roderick would react if he knew the person ultimately responsible for that picture is also responsible for his sister dying.'

'She's not dead yet,' the Doctor pointed out.

'But she will be,' said Peri. 'Unless we get our act together, she'll be dead in days.'

A breathless maid hurried into the room. 'Please, miss, Miss Jane is asking for you.'

Peri sighed. 'Just going away and letting the thing kill her would be wrong, right?'

'Yes,' said the Doctor sternly. 'It would.'

Peri read a novel to Jane until the sunlight faded. It was not the sort of novel she favoured, being full of women with heaving bosoms sighing heavily over men whose cold hearts would eventually be melted, probably by all those heavy sighs. 'Don't stop!' screeched Jane as Peri marked her place and shut the book.

'It's too dark to read any more, even with a candle,' Peri pointed out. 'And you said a brighter light would hurt your eyes.'

Jane put a hand on her forehead and sighed a piteous rather than a heavy sigh, although just as fictional. 'How I do suffer,' she said (also piteously). 'I fear I will not live long enough to be able to call you sister.'

'Don't say that!' said Peri, meaning it literally. The thing was that Jane would be either saved or dead before the wedding and either circ.u.mstance meant that Peri would definitely not be turning up at St George's Hanover Square in a bridal gown on the appointed day.

The next morning, Peri was grabbing a few quiet moments in the morning room when she heard a knock at the door. She sighed at the thought of having something else to deal with. Already that day she'd had to supervise the cooking of dainty dishes to tempt an invalid's palate (as ordered and she did mean ordered by Jane; read yet more of that tiresome novel to Jane (Miss Hyde the governess had been supposed to take a turn but had mysteriously disappeared just when she was needed), and listened as Jane outlined all the beauty treatments she was undertaking to look her best for the wedding (if she lived that long). Jane was so living up to the role of a self-absorbed delusional malingerer that Peri had to keep reminding herself that an evil alien was actually draining the girl's life force. Jane was actually dying.

Now, finally, thankfully, Peri was getting a break from her sister-in-law elect while lady's maid Yvette applied those beautifying unguents and powders and creams. A maid showed a thin, scholarly-looking man into the room and announced that he was Mr Peppercorn.

'I'm afraid you've had a wasted journey, sir,' Peri said, rising to greet him. 'Unfortunately Miss Pottinger is too unwell to attend her studies. Please accept my apologies for neglecting to send word to you.' It was deliberate neglect, of course. The alien they were hunting had to be someone who visited Jane regularly (utilising a very useful ability to blend in as though he or she'd always been there, of course) and her music master was on that list. 'But perhaps I could beg a favour while you are here.'

'Anything, anything!' gushed the man, who seemed incredibly relieved that he wouldn't be spending an hour alone with Jane Pottinger.

Peri gestured towards the piano. 'Play for me? It would be such a treat. We don't have pianos back home in America.' That was a test. The Doctor had discoursed for some minutes on the history of the piano. If Mr Peppercorn didn't contradict her mistake...

... which he didn't...

... then it probably meant that he either wasn't that interested in transatlantic instruments or he was being polite in not contradicting her. So it signified nothing. It certainly didn't mean he was an alien villain masquerading as a tutor to drain the life force of an irritating girl.

'Oh, charmed,' said Mr Peppercorn. 'Delighted!' He crossed to the piano and began to play.

Or maybe it did mean he was an alien villain masquerading, etc., etc.! Because that man sure could play.

'Don't stop!' Peri told him. 'Back in a minute!'

She was back well before the minute was up, dragging the Doctor with her. 'Isn't Mr Peppercorn good, Doctor!' she cried. 'So good it scarcely seems human.'

'A masterly performance,' said the Doctor as the music master finished with a flourish. 'And not a piece I recognise. Your own composition?'

Peppercorn nodded. 'Indeed. A humble offering of my own. Not quite in the cla.s.s of Herr Bach or Herr Mozart...'

The Doctor popped out of the room for a second then came back in. 'You're too hard on yourself! Of course, few can compete with Johann Sebastian Bach, born Eisenach, Germany in 1685, best known for his Brandenburg Concertos, or Wolfgang Amadeus Mozart, born 1756 in Salzburg, best known as a cheese made from buffalo milk commonly used on pizzas.' He frowned and popped out of the room again, returning swiftly. 'That is to say, best known for operas such as The Marriage of Figaro and The Magic Flute but really, sir, you are approaching them in skill.'

The music master flushed so hard it could be seen even through the thick white make-up he was wearing. 'I am covered in confusion, sir,' he said to the Doctor as he left the room, bowing and sc.r.a.ping. 'Thank you for such kind words.'

'So? Is he our guy? He's a musical genius!'

The Doctor wrinkled his nose. 'Perhaps a genuine one. After all, we've found no evidence so far that our foe utilises the stolen gifts himself. And Jane has gone rapidly downhill since we arrived yet Mr Peppercorn only visits her weekly. I don't think he's our man.'

'Please, miss, the mistress is asking for you,' said the maid who'd just come in.

'Oh. Great,' said Peri.

Yvette's lotions and potions definitely hadn't done the trick. Jane was looking really ill, much more so than previously.

'My body aches from the soles of my feet to the roots of my hair!' she cried. 'Brambles are clawing their way through my throat!'

She'd been sick too, Peri noted. 'Who's been in to see you this morning apart from me and Yvette?' she asked.

'No one,' Jane moaned.

No one. So if the culprit wasn't Peri (and obviously it wasn't)...

'Doctor, I need to know the French for "So, are you a genuine lady's maid or are you an evil alien?" Hey, come back! I asked you a question!'

(Pause.) 'Oh, Peri, did you say something? I popped out to check on the weather.'

'I asked-'

'Yes, yes, yes. C'est: Alors, vous tes la femme de chamelle d'un veritable dame ou tes-vous un etranger mal?'

'Thanks.'

'Yvette! Alors, vous tes la femme de chamelle d'un veritable dame ou tes-vous un etranger mal? Why are you laughing? Er, I mean, er, pourquoi... Hang on, what's laugh? Ri-something, I think.'

'I think you mean femme de chambre, mademoiselle. Instead you have enquired if I am a camel woman.'

'Oh. Well, are you?'

'No, mademoiselle. I am not a ruminant quadruped of any kind.'

Peri gloomily turned away then turned back with an 'Aha!' and a 'J'accuse!' 'That's pretty fancy language for a lady's maid!' she continued. 'Suspiciously so.'

Yvette shrugged. 'Once upon a time I was educated, mademoiselle. The Reign of Terror made it necessary for me to change both my country of residence and my station in life.'

'Oh,' said Peri. 'Sorry.'

Peri rejoined the Doctor. 'I thought I was on to something. No good, though.' She sighed (yes, again). 'I just keep thinking of all the ones we didn't save. That Stone Age computer pioneer. Or that little chimney-sweep mathematician.'

'The galley slave who could have been an astronaut... The crossing sweeper who should have been a surgeon...'

'And now Jane. An admittedly annoying Regency miss who could be a great what was it again?'

'An anpholier.'

'Yeah. One of those. An admittedly annoying anpholier. Whatever that is.'

The Doctor sighed. 'I can't explain it to you.'

'Because I'm too dumb?'

'No. Because you don't have the vocabulary.' He sighed again. (Everyone was sighing a lot. It seemed to be the done thing in Regency times). 'Maybe you could just download the app onto your smartphone.'

Peri blinked.

'See?' said the Doctor. 'Thirty years after you left Earth, that sentence would be understood by every man, woman and child. But it means nothing to you. The Human Genome Project! The World Wide Web! Texting! DVDs! The Large Hadron Collider! Dolly the Sheep!'

'Pardon?'

'Exactly! All scientific advances only a decade or three from 1984.' The Doctor was throwing his arms wide now, a Shakespearean actor writing his own lines. 'How much more difficult do you think it would be to explain something a century or more in your future? All you need to know is that an expert anpholier would have a rare skill. And, incidentally, one that could save lives. A lot of lives.'

'But only if Jane dies. Hmm. One really irritating life against maybe hundreds...'

The Doctor gave her a stern look.

'I didn't mean it,' she muttered. 'You know I didn't. Even if you offered me a million pounds...'

'A million pounds is probably small change to the Potentialiser.'

'The Potentialiser'. That was the name they'd given the monster they were pursuing.

Peri had known talented kids back home. There was Sadie Turtle, who won every tennis championship going. Randall Schuyler, who skipped so many grades he was practically still in diapers when he sat his SATs. Then there were also kids who didn't shine, but whose parents made them try everything piano lessons, swimming lessons, karate lessons, art cla.s.ses, chess, baseball, football, hockey, ice-skating, everything in the hope of finding that one thing that would make their child rise above all the rest. Those were the ones who'd pay for the Potentialiser's services.

Because what the Potentialiser did was this: he or she detected the potential for a talent, a talent that by way of circ.u.mstance would never come to fruition, because its owner was born in the wrong place or the wrong time or the wrong social stratum or with deficiencies in health or wealth that meant the genius wouldn't or couldn't be realised. And when the Potentialiser had tracked down the would-be ballerina or artist or scientist, he or she would extract that potential and give it to someone who could use it. Which would be fine. If only the original subject didn't die during the extraction.

The Doctor had worked out a way of tracking the Potentialiser's victims, but until now they'd arrived too late to either save the victim or catch the Potentialiser. This time, however, he'd done some clever thing or other to the TARDIS and had bought them a few days' grace. Hence Miss Perpugilliam Brown's lightning betrothal to Lord Roderick Pottinger following his rescue of her from a vile gang of attackers (attackers who had to attack four times before Lord Roderick got the message, not that they minded, being handsomely paid for their banditry). And here they were, with unfettered access to Roderick's sister, the intended victim, over the course of several days, and no more clue as to how to save her than when they first arrived.

'I thought it might be Yvette,' Peri said. 'But it looks like she's genuinely French. She definitely speaks the language.'

The Doctor raised an eyebrow. 'Far be it from me to cast aspersions on your reasoning, but not only is it likely the Potentialiser can be understood in any language, so can we. TARDIS gift. Doesn't prove a thing.'

'You still managed to get the translation wrong, though, TARDIS gift or no TARDIS gift,' grumbled Peri. 'Turns out I asked her if she was a camel. Hey! Do Regency people know about camels?'

'Just a second,' said the Doctor, jumping up and exiting the room.

Peri was getting just a little bit fed up of this. She crept across the room and quietly opened the door a crack.