Peter had a headache. His instincts were driving him crazy. They were refusing to accept the scene in front of him. He was also trying and trying, but he just couldn't think exactly how they'd got to be in a ruined shrine in second-century Rome.

"What happened to your nose?" Rose suddenly asked. Peter looked down and saw that it had been bleeding recently. It hurt to touch it too, as though it had been stuck.

"I don't know, I can't remember" He said as he wiped it clean as best he could.

"You got a headache too?" Rose asked, seeing him clutch his head. Peter nodded.

"Not just that, something's wrong, my instincts are unsettled, where are we? How'd we get here?" Rose shrugged. She tried to establish the facts. She was Rose Marion Tyler, from twenty-first-century London. She used to live in a flat on the Powell Estate with her mum, Jackie, until she'd met up with – of course, with the Doctor!

The Doctor, the last of the Time Lords, who travelled through time and space in his ship, the TARDIS, which was bigger on the inside than the outside! So was that how. . . ? No. She and Peter hadn't come back here with the Doctor, she knew that for a fact. The last time they'd seen the Doctor was in London, when they'd gone to the British Museum and seen the statue of Rose as Fortuna. So how had they got to ancient Rome? Teleport? Matter transmitter? Must be something like that. Or had they been hijacked by aliens? Yes, that had to be it. It wouldn't be the first time that had happened to them. And what had been going on here?

She had hazy memories of Vanessa – yes, that was Vanessa petrified on the floor –and Ursus, the sculptor, who had fallen on his dagger and died, but quite how it had all come about she really wasn't sure. Hang on. That thing in the box, that must be the alien that kidnapped them! No. No, it wasn't, it was something else. . . A god. . . Rose's brain began presenting her with a plausible picture. If she didn't think too hard about things, everything made sense. But she was Rose, and she was going to think hard if she wanted to. Think, think, think. . .

"Oh, I wish I could remember how we got here!" Peter suddenly said in frustration. There was a crashing sound in his head.

"Oh, all right, if I must," Said the dragon-like creature. And suddenly the last few minutes became as if a dream. Rose and Peter knew how they'd got there and why they'd got there, and most of all they realised that the Doctor wasn't there any longer. . . Rose stumbled backwards, shocked and wary. The Doctor. . . was gone. There was no sign that he'd ever been here.

"Doctor!" Peter shouted. "Doctor!" There was no response. So distracted were they that it was a few moments before they noticed what was happening to Ursus's body. It was the sacrificed lamb all over again. As they watched, sickened, they could see the sculptor's once-deadly hands begin to bubble and melt as though made of wax. Finger bones showed briefly as the flesh dripped away, but then melted in their turn. Eyeballs lost their substance, began to seep down pallid cheeks, but were then sucked back through the sockets to combine with the facial soup that was now forming. Empty blood vessels, muscles, withered lungs and a decaying heart all flashed into view, like a series of diagrams from a biology textbook, before they too melted away. And then there was just the puddle curdling on the floor, first expanding and then decreasing as the liquid was sucked away; a tide that kept turning.

All being absorbed by the little scaly creature in its cardboard box. The last of Ursus vanished with a noise like a straw sucking up the dregs of a milkshake. Rose had seen death far too often, but still she found herself clapping her hands over her mouth to try to keep in the bile that was rising in her throat. Peter too was well acclimatised to violent sights but it didn't stop him paling and clutching his nose against the temporary but still vile smell of decay.

"I'm much obliged to you," Said the creature. "That should keep me going for a while." Rose tried to put the sight out of her mind, tried to concentrate on something more important instead.

"Where's the Doctor?' She said."What have you done with him?"

"The Doctor?" Said the beaked dragon. Its voice now was very different from the tones it had used in its Minerva guise, more androgynous and tinnier. "There's been no doctor here."

"Yes, there has!" Peter insisted. "You called him by his name. You must know who he is."

"I think you must be mistaken," Said the creature. "I have done no such thing. No doctor was ever here. Ask anybody." Rose laughed disbelievingly.

"There's no one to ask! The Doctor's gone, Vanessa's been rockified and you've just slurped up Ursus like a cat with a saucer of cream! Look, who – what – are you anyway?" The little creature clacked its beak.

"I am a GENIE," It said. Rose and Peter gaped. "A genie?"

"Indeed. A Genetically Engineered Neural Imagination Engine."

"A what?" Peter questioned.

"A GENIE."

"Do you mean – you can't mean – I mean, you're not a being that grants wishes. . . " Rose said

"You are incorrect. I am not not a being that grants wishes."

"Pardon?" Said Rose.

"That is to say, I am a being that grants wishes. That is the function for which I was designed and built."

"By Vanessa's dad?" Peter asked.

"Salvatorio Moretti was my primary creator, yes." Rose and Peter were starting to piece it all together. "And so when Vanessa wished she lived in ancient Rome. . . " Rose began.

"I granted her wish. Placed her in the correct time frame, gave her appropriate language abilities and clothing. It took a considerable amount of power to do so, but I was lucky enough to be at that time in a place which possessed extensive energy reserves. It is fortunate that she never sought me out and required me to return her to her previous abode, as I fear I would have had some difficulty acquiring the necessary energy."

"I don't think Vanessa knew anything about you. She had no idea how she got here." Peter told it.

"Ah," Said the GENIE, suddenly sounding slightly embarrassed. "Although I had to accompany my wisher in order to facilitate the transfer in time, I fear a slight miscalculation on my part led to us being separated on arrival in this era. However, considering the fact that I had succeeded in forming a working theory of time-travel and then almost instantaneously engineered a way of putting it into practice and transporting us not only over two millennia in time but several hundred miles across space, I think such an occurrence barely even counts as an error."

"Yeah, the Doctor tries to claim that too," Said Rose. "It doesn't wash with him either." A lump suddenly came to her throat, thinking about the Doctor. She tried to distract herself again. "And Ursus!" She said.

"He wished something about creating beauty in stone. He probably even mentioned wanting to use his hands to do it. But he didn't mention anything about sculpting or skill with a chisel, so you went ahead and sorted it however you liked. It's hardly my fault if people fail to be sufficiently specific. Anyway, he didn't seem to mind," Commented the creature.

"Well, no, because he was obviously a psycho-nutter," Said Rose.

"That's an understatement" Peter muttered. "But, you know, just because someone says 'I wish' doesn't mean they expect a totally literal interpretation" He told the creature. Rose's stomach suddenly dropped as a scene from earlier forced itself into the front of her brain. Her legs threatened to give way and she hastily sat down. Then she realised she was sitting on Vanessa and stood up again.

"I said. . . " She began, but couldn't bring herself to go on. She took a deep breath. "I said, 'I wish he'd never come here.' I said it to Peter and you. . . " She shook her head fiercely. "What am I talking about? This is mad. Genies are myths, something from the Arabian Nights, and I don't believe in you or your wish-granting thing." The GENIE drew itself up, little scaly monkey paws gripping on to the side of its cardboard box.

"Try me!"

"All right, we will!" Said Peter defiantly.

"Hang on." Rose cautioned before turning to the GENIE "Do we only get three wishes or something? Because if – if – it's true, and I'm not saying I believe it is, I don't want to waste them all." The GENIE sighed.

"I will continue to grant wishes so long as I have sufficient power to do so. However, limiting wishes is in no way a bad idea. I may have to consider it. Otherwise my resources will be constantly drained. . . "

"OK," said Peter, thinking hard. "Something really simple. That can't be misinterpreted. And that won't harm anyone." Rose and he considered for a moment before Rose got an idea.

"Right, I wish I had a bag of chips. Made from potatoes. Hot. With salt and vinegar. And a fork to eat them with. They don't have forks here – or potatoes – so if you manage that. . . "

But before she had stopped speaking, they heard that crash of thunder again. And then suddenly she was holding a bag – a paper bag, grease already starting to soak through from the fat golden chips inside it. Gingerly, she forked one up and took a bite. It was the perfect chip, not too soggy and not too crisp, just the right temperature, with a delicate sprinkling of salt and vinegar. "Wow," She said. "Well, if we're stuck here for ever, at least we won't starve. . ." Stuck here for ever. No Doctor No TARDIS?

A sudden thought occurred to Peter. "Hang on," He said. "Can't we just wish wishes undone?"

"I don't advise it," Said the GENIE, sniffing.

"Why not?" Asked Rose indignantly.

"It's perfectly obvious," Said the GENIE. "This 'Doctor' never came to Rome, so he was never here, so you never wished for him not to be here, so I never granted that wish, so there's no wish to undo."

Rose's head hurt. She mechanically put a chip into her mouth and chewed.

"Well, what if I wished – this isn't a wish, all right, I'm just working things out – for Vanessa to be unstoned," She said through a mouthful of potato. "That's not undoing a wish, because that was all about Ursus's hands, not Vanessa becoming a statue. So it'll work, yeah?"

"It's a technicality," Sniffed the GENIE. "Anyway, I'm in the wish business, not the advice about wishes business."

"You're just having a laugh," Said Peter. Rose nodded.

"Yeah you're going to let us go ahead and wish it, and even if it works, you're going to give us the ability to turn stone to flesh with our hands, so every time we touch a rock it becomes a great blubbery lump or something, aren't you? Or she'll become a. . . a living statue, or a dead body, or something awful." The GENIE sighed.

"Well, really, it's hardly my fault if people choose not to be precise in their utilisation of language. I merely act with regard to the logic circuits with which I was constructed. Can I help it if people do not do the same?"

"We don't have logic circuits," Said Peter.

"That I was inclined to suspect," Said the GENIE.

"You know your a very snarky little thing." He could have sworn the creature chuckled.

"But that doesn't mean we can't be logical,' Rose pointed out "Like, I'm thinking about my wish here. If I. . . no. How about if. . . no. Or. . . no." She clenched her fists. "Ooh, do you know how annoying this is?"

"Do you wish me to know?" Inquired the GENIE.

"No!" Rose and Peter cried out simultaneously.

"OK, I've got it. Foolproof." Rose laughed. "Look at me, I'm a genius!" "She got out once again the empty glass phial that had held the Doctor's miracle cure. "The stuff that was in this, it turned people back from stone, right? So. . . I wish it was full of the same stuff again." There was the booming sound inside their heads that they'd come to expect. And then. . .

"Yes!" Peter said The phial was filled right to the top with the emerald-green liquid again

"There, that wasn't so difficult, was it?" Said Rose triumphantly.

"As a matter of fact, it was extremely complex," Replied the GENIE. "An astonishingly difficult formula. I have never come across anything like it before."

"Well, as long as it works," Said Rose, not really listening. She pulled out the stopper slowly, carefully, and then tilted the vessel so a single glistening drop fell on the prone Vanessa. 'Miracle' was the right word, she thought. The whiteness of the marble suddenly burst into colour, as if a whole palette of paints had been splashed on to it. The colours spread and merged until there was not a speck of stone left and then, with a shiver, a real live girl was lying face down on the ground. "Wow,"

"I know, I'll never get use to it myself" Peter added as he took hold of Vanessa's arms and helped her to sit up. "OK, before anything else – don't say you wish for anything. You probably want to start with 'Where am I?' and 'What happened?'" He said.

"Yes, I think I do," Said Vanessa warily.

"Well, one, you're still in that old shrine place, and two, Ursus turned you into stone but now you're back." Vanessa jumped and darted an anxious glance around the ruined building. "Ursus! Where is he?" Rose waved a hand at the GENIE.

"Your scaly friend over there went and ate him."

"My friend? Ate him?" Vanessa did a double take. "That's. . . that's the box.. "

"That's the box that was in your father's study back in the twenty-fourth century," Rose completed for her. "And that thing in it is a GENIE, made by your dad, and it granted your wish to come back here. . . "

Rose and Peter explained everything she'd learned about what had been happening, finishing with the disappearance of the Doctor and their own wishing experiences. To their slight surprise, Vanessa didn't seem as freaked out by it as they'd expected. Perhaps when you'd spent the last few months living in a time 2,000 years before your own, you took things more in your stride. Although. . . well, actually Vanessa looked – happy. Almost verging on overjoyed.

"What?" Said Rose. "Did I say something funny? Because I don't think I did." Vanessa's eyes were shining.

"Don't you see? All I have to do is wish to go –" Peter quickly clamped a hand over Vanessa's mouth before she could finish

"Didn't you hear what I was saying? Be careful what you wish for!" But Vanessa didn't seem put off.

"I can get home! Now I know what brought me here, all I have to do is w–" Peter's hand slammed back in place.

"Whoa whoa whoa! If you w-word to go home, where's that leave me, Rose and the Doctor? How are we gonna get him back? Anyway, the GENIE says it can't reverse wishes, so who knows if it can take you home anyway? I mean, if it could do that it'd probably have wished itself back by now." The GENIE, which had been listening with interest, gave a big sigh.

"Regrettably, my creators chose to limit my powers so wishes can only be granted for others. Not myself." Rose frowned.

"Right. But, look – this is not a wish – would you be able to get Vanessa home – safely – if she, er, expressed a desire for it?" The GENIE considered.

"I may be able to do so," It said. "Of course, as I explained previously, time travel over such a considerable distance requires a great deal of power." "Yeah, I know," said Rose. "But if you managed to do it once. . . "

"On that occasion I was able to obtain energy from the global electricity supply," It informed her.

"You mean – that's why all the lights went out?," Said Vanessa, as Peter removed his hand. "That was you?"

"Well, quite. What did you expect?" Said the GENIE rhetorically. "However, there is no such electricity supply in this primitive place. I have been forced to adapt myself to obtain energy in a much more basic form." Rose felt sick again.

"A goddess must eat" She quoted. "That's where you've been getting your energy from." She turned to Vanessa. "That's why it absorbed Ursus's body."

"Indeed," Agreed the GENIE. "However, I fear I do not have sufficient fuel to grant any further time-travel wishes." Peter raised an eyebrow:

"Well, we're not killing anyone for you! Look, how much more do you need? Maybe we can, I dunno, pick up a couple of steaks or something." The GENIE was quiet for a moment, pondering. Finally it said, "I have calculated the energy that would be required to get to the year 2375."

"Yes?" Said Vanessa eagerly. "Assuming my last energy intake –"

"You mean" Dead body" Put in Rose.

"– is regarded as an average," Continued the GENIE, "I calculate I would need 1,718,902 times that amount in order to grant such a wish." For once, Rose and Peter were speechless.