The Doctor looked up from the TARDIS console and smiled warmly. Grace had just come from the inner corridor and set a tea tray on the table in his rest area.

“Good idea,” he agreed, leaving his calibrations and coming to settle himself on one of the old-fashioned but comfortable armchairs. “Tea. Just what a Time Lord needs after a fifty million year flight.”

Grace giggled. The fifty million years had taken forty minutes so far. He had promised they would take no more than another thirty to get back to San Francisco.

“It was beautiful, wasn’t it,” she said as he came to sit with her. “The landmass we call America… back before humans existed. Funny to think that the Nevada desert was beachfront property. The State of California – everything west of the San Andreas fault, was ocean.”

“It took a mighty seismic shift to throw up all that dry land,” The Doctor added. “Pushing the Sierra Nevada mountains up from the ocean bed, along with lots of fossilised seas life to fascinate scientists in the future. Yes, the Creation of worlds is a wonderful thing.”

“Creation of WORLDS, plural.” Grace smiled. “For me, one world is enough. You’ve visited hundreds of them. Thousands.”

“Only two ever meant very much to me,” The Doctor answered her. “Gallifrey… home… and Earth… my home when I couldn’t go back to Gallifrey… and where some of the most precious people I’ve ever known came from.”

“Don’t get soppy,” Grace told him. But she didn’t mean it. It was gratifying to know that she was one of the reasons he came back to Earth time and time again. These trips he took her on, away from the pressures of her life, were as much for his satisfaction as hers.

“Back to reality in twenty minutes,” he said. “Ten o’clock in the evening. An early night with cocoa and biscuits for you. A peaceful sleep before that big operation scheduled for the morning.”

“A heart and lung transplant,” Grace noted. “A young woman with cystic fibrosis. The matching organs are being flown in from Canada. I’m working with a top transplant doctor from Vancouver. It’s a twenty hour procedure. We work together with the theatre staff rotating after six hours. It’s hard work. But we’re optimistic. We can give the patient a new, healthy productive life.”

“You do great work, Grace,” The Doctor told her. “Your world needs you. That’s why I bring you back to it even though I am tempted to take you away with me forever.”

“Getting soppy again,” she warned him. But she didn’t mind. The fact that she had an important job was the reason she didn’t let him take her away with him forever.

The only reason.

He leaned close to kiss her. She appreciated the kiss thoroughly, at least until the TARDIS console whistled piercingly and he sprang up and ran to attend to it. Grace recognised that the sound was an urgent one and quickly joined him at the navigation control. She noticed that they were in ordinary space, not the time vortex, and that Earth in all its blue, green and white beauty was slowly revolving beneath them.

A quiet Earth with no light pollution from cities when they were over the night side. This wasn’t her century, yet.

“It’s the proximity alarm,” The Doctor explained, reaching to turn off the noise. “Nothing to worry about. The TARDIS wanted me to know that I was close to an asteroid as it passed near Earth’s orbit. That’s nothing to worry about, either. In your time the scientists will catalogue it as 2005 YU55. It isn’t even special enough to get an interesting name. It’s about the size of an aircraft carrier. The most remarkable thing about it is that it is dark-coloured in the visible wavelengths so it is virtually invisible from Earth except through radio telescopes – which haven’t been invented yet, since we’ve come out of the time vortex in the year 2037 BC.” The Doctor chuckled softly. “The year Emperor Shen Nong discovered how to make tea – with a little help from me. Other than that, this isn’t anything significant. We can leave the asteroid alone and carry on back to the twenty-first century.”

“Um….” Grace was glancing idly at the environmental monitor when something grabbed her attention. “Are you sure about that, Doctor? Maybe you ought to look at this.”

The Doctor moved around the console and looked at the monitor with her then he tapped manically at the extended keyboard, only part of which used the alphabet as Grace knew it. The monitor filled with data and then cleared again to show the schematic that the TARDIS computers had automatically created in response to the proximity signal.

“It’s impossible,” he said.

“I didn’t think anything was impossible around you, Doctor,” Grace remarked.

“Well, ok, not impossible,” he admitted. “But very improbable. Do you realise what this is?”

“It’s a three-dimensional map of the asteroid that shows that it isn’t solid rock. It’s more like a skin of rock around…. Well, if I had to compare it to anything… you said it was about the size of an aircraft carrier. That’s what the inside looks like… it has square cells like cabins aboard a ship and long sections connecting them that could be companionways… wider sections that could be communal areas….”

“And….”

“And lifesigns…. About two thousand of them.”

“It’s not an asteroid. It’s a spaceship….”

“Disguised as an asteroid?”

“Perhaps not deliberately. If it’s been in space a long time it might have acquired a shell around it, millennia of space dust accretion….”

“That’s possible?”

“Oh, yes,” The Doctor answered. “I’ve seen that sort of thing before. I came across a moon once with a space ship deep inside its core. It had been travelling for fifty thousand years on autopilot with a whole race of people, along with plants, animals, all in cryogenic sleep within it, waiting to find a new home. They got there in the end. I went to check. Their moon slid into synchronous orbit with the existing moon of a beautiful and uninhabited world and they woke to a new life. It was rather wonderful to see it happen. It really restored a tired and universe-weary old Time Lord’s faith in Creation.”

“This is my first space ship,” Grace said as his anecdote finished. “You’ve taken me to Gallifrey and The Eye of Orion, the Horsehead nebula, the rings of Saturn, and a whole history book of Earth time periods. But I’ve never seen an actual space ship.”

“Well, now’s the time,” The Doctor told her. “We can’t just leave this alone. We don’t know what they might be here for. They could be sight-seeing, or they could want to invade, steal the secret of tea from Shen Nong, anything. We need to find out what this is all about.”

“It might be dangerous?”

“Are you worried?”

“Can anything be worse than The Master? And he was one of your lot. Let’s go and look at this space ship.”

The Doctor checked the environmental monitor and noted that the air aboard the ship WAS air by the definition he and Grace both defined it. The oxygen level was lower than either were used to, but not dangerously so. He set the co-ordinates for a section where no organic lifesigns were registering and pressed the dematerialisation switch.

The TARDIS rematerialised in a large cupboard. The Doctor and Grace stepped out and looked at a row of used and new robot parts.

“But we DID see organic lifesigns,” Grace pointed out.

“That’s not unusual. Many organic species use robots as workers, slaves, soldiers. The significant thing is that these robots have humanoid forms. That almost certainly means that the organic species is humanoid.”

“That’s good?”

“It means we’ll probably look like them. People tend to be fearful of what isn’t like them. You’d be repulsed by the descendants of lizard lifeforms and they would be equally disturbed by you. But if we’re dealing with people who look more or less like us that’s half the job of making contact dealt with.”

The Doctor reached for the door out of the cupboard. He stepped onto a ship’s bridge, noting that it was ‘manned’ for want of a far more appropriate word by humanoid shaped silver robots. They had moulded faces with no range of expression and eyes that were glowing blue lights. It was several moments before any of them noticed the new arrivals. When they did, one stepped closer. The Doctor grasped Grace’s arm and pulled her closer to him.

“Stay still. It just wants to scan us to identify our species.”

Grace stood still. A green ray of light came from the robot’s eyes and enveloped them for several seconds. When it stopped the robot tilted its head forward in something like a bow.

“You are welcome elders,” it said in a smooth voice that was not at all mechanical or staccato, but nevertheless lacked any intonation to make it Human-sounding. It was a reassuring voice, all the same. The word ‘welcome’ was always encouraging.

“Elders?” Grace questioned. “What does it mean?”

“It scanned our DNA. It recognises that we are more evolved than the humans on Earth presently. You are taller than your ancestors, with stronger bones and teeth. Even your blood is different. You carry immunity to diseases that killed people four thousand years before your time. Obviously MY DNA is even more advanced than yours.”

“Obviously,” Grace replied with a slight note of sarcasm. “So they know that there are people on planet Earth….”

“You are elders from the destination world, come to witness the Landfall ar the end of the great migration?”

“Um….”

“Ah!” The Doctor exclaimed. “This is a generation ship. Now I understand. Please, take us to the habitat. We should meet with the travellers as soon as possible.”

“Of course, elder,” the robot answered. “Come this way.”

The robot turned. They followed it out of the bridge and along a wide, brightly lit corridor. They were aware that there were two more robots behind them, but neither of them felt any sense of danger from that. They had no reason to expect any threat from the mechanical crew of this unusual ship.

“What IS a generation ship?” Grace asked. “You seem to know what’s going on around here.”

“Yes,” The Doctor answered. “Yes, it’s a very interesting….”

He stopped talking. The robot had directed them through an open door. But now that door slammed shut behind them and they heard the ‘thunk’ of a heavy lock sliding into place. They were prisoners.

“What… happened?” Grace asked.

“Oh dear,” The Doctor answered. He looked around the room. It was bare except for a bench moulded to the wall. There didn’t seem to be any obvious way out apart from the locked door. It was a perfect prison cell.

He sat down on the bench. Grace sat beside him.

“Generation ships…. Were the idea of a humanoid race called Emenelles. They were over-populated and running short of resources so they had the idea of sending whole communities out into space to look for new worlds to live on. They are genetically remarkably similar to your own race. They wouldn’t be out of place on Earth. I suppose that was the idea. Earth was a compatible planet.”

“So they sent this ship with a group of colonists to make a new life on Earth?”

“Not exactly. The Emenelles had very powerful telescopes, capable of seeing across the galaxy. They identified suitable planets to colonise. But they didn’t have any kind of hyperdrive. They knew it would take a thousand years or more for their ships to reach their destination planets. The people who boarded knew they were going to live out their lives in space, aboard a space ship. Their children would, too, and their children’s children. Generations would live and die in space before the ship arrived at the destination.”

“Like in the bible… the people of Israel in the wilderness for forty years, travelling to the Promised Land… knowing some of them would never see it.”

“Very much so,” The Doctor answered. “Though at least they had the hope that their children would see their journey’s end. The people aboard this ship have never known any life but the ship. They haven’t even second hand knowledge of the world they left, and the world they are coming too must seem like a myth to them, something they can hardly imagine really happening in their lifetime.”

“It’s going to be a huge surprise to them, then?”

“It’s going to be a massive culture shock to them. They’ve never known any space bigger than their recreation hall or the mess room with walls and ceilings bounding them. They’ll feel giddy looking at the sky, and the horizon will terrify them. But it is what they will have been taught to expect in the ‘new world’ or the ‘promised land’ or whatever the phrase has been passed down through the generations. I’ve even come across people who have turned it into a religion, and when they reach the planet they think they’ve died and gone to the heaven promised at the end of their time of ‘struggle’. I think they’re probably the happiest in many ways, because they truly believe that they’ve gone to a ‘better place’.”

As The Doctor talked, he was scanning the walls and ceiling with his sonic screwdriver. He went on to explain that the success of former ‘generation ship’ populations differed from planet to planet. Some went on to successfully colonise, forgetting after a few generations had been born on the world that they were not indigenous to it. Others struggled and failed within a few generations. Much depended on how they had been prepared for Landfall. Some had come to expect paradises where they would never have to work and food was plentiful, and were shocked when they found that they had to hunt and plant crops and build their own shelter. Others fought among themselves for the land, splitting into factions too small to be viable. But whatever happened, they had no choice. Once the ships arrived at the destinations there was no going back. The robots were programmed for a one way trip. When it was over, they were de-activated. The ship would fly into the sun and be destroyed. They had to make the best of it one way or another.”

“So….” Grace began. But The Doctor’s behaviour distracted her. He was standing on tiptoes reaching with his sonic screwdriver to a patch of ceiling that looked just like any other at first. Then a square panel appeared in it. He adjusted the sonic and applied it again. The panel slid back.

“There’s ALWAYS an access panel somewhere,” he said. “Do you want to go first or shall I?”

“We’re escaping?”

“Of course. You don’t think I’m going to hang around here forever?”

Grace went first, climbing up on The Doctor’s shoulders. When she was safely inside the crawl space above he jumped and grabbed on and swung himself up into the gap.

It was dark. He used the sonic in penlight mode to see the narrow access tunnel that stretched beyond the confines of their cell in both directions.

“That way, I think,” The Doctor said and set off crawling on his hands and knees. Grace followed, glad that she was wearing a trouser suit today. The floor of the tunnel was a closed metal mesh that would have been painful on the knees. As it was, her hands were starting to feel sore after a hundred yards or so.

“Doctor, I am meant to be doing surgery when I get back. I don’t need blisters on my hands.”

“Not far, now,” he promised. “I want to see what these robots are up to. Something isn’t right.”

The tunnel widened out into a larger space. Light came from below and a curious noise like an old fashioned computer programme loading.

“What is it?” Grace asked.

“The robots talking to each other in machine code,” The Doctor answered. “Actually, arguing with each other, would you believe?”

“Ordinarily, I wouldn’t. Robots aren’t meant to argue. That would imply a level of cognisance and reasoning that….”

“Hush a minute,” The Doctor said raising a finger to his lips. “It’s not easy translating machine code. I’ve got to concentrate.”

Grace really wanted to ask how even a Time Lord could actually translate machine code in his head. That was possibly the most incredible thing she had ever seen him do. But she was absolutely bursting with anticipation. What WAS this all about? Why were the robots arguing? Why had they been imprisoned by the robots?

Of course they might have forgotten all about them and were just discussing navigation in a heated way.

“Oh dear,” The Doctor said after a while. “So that’s what it’s all about.”

“What?” Grace asked. “Come on, tell me.”

“The Landfall – it’s never going to happen. The robots aren’t going to let it happen. At least, one faction of them won’t. That’s what the argument is about. That one with the red glow in his eyes is the leader of the rebels.”

“Rebellious robots? I don’t like the idea of that. Are they armed in any way? Can they kill?”

“No to both questions. They’re completely unarmed and programmed with an aversion to physical violence against each other or the organics they serve. That’s why we were tricked into the cell, not manhandled in any way. But this argument is bringing them to a crucial point. They might well override their programming if it goes on much longer. And that would be bad for them, us, and the generation of humanoids aboard.”

“What’s the problem, exactly?” Grace asked. The argument was still being carried out in machine code, but there was an agitated tone and the rebel leader was trembling with emotions she could hardly imagine an artificial intelligence having.

“The loyal faction, led by the one who scanned us earlier, that one there… is demanding that we are set free and the Landfall initiated. The rebel leader is insisting that the ship is allowed to continue drifting through space forever, with us kept as hostages along with the generation. No, hostages isn’t quite right. He means passengers. But passengers usually know when and where they’re going to get off the ship. If he has his way, we’ll be here for the rest of our lives.”

He paused. Grace knew this was her cue to ask a question starting with ‘how, what, why….’ But she decided she had done enough of that. After a while he carried on talking without her prompt.

“The robots have been in charge all through those thousands of years, looking after the people. They don’t age, of course. They need the occasional spare part, but mostly they go on forever. But the trouble is, artificial intelligence IS an intelligence, and of course they’ve worked out what happens next. They know that once the people start their new life their work is done. And that means that their lives are over. They will automatically deactivate before the ship heads towards the nearest star to be destroyed.”

“They don’t want to die?”

“Exactly.”

“I… kind of understand their point. At least I think I do. They really do think of it as ‘death’ in the way we understand it?”

“Yes, they do. And they don’t like it. They’ve been avoiding the end of the journey for millennia. That’s why the ship has accreted the outer skin of rock. The robots might even have made it happen, turning the hull magnetic and attracting rocks and dust to it. The original flight plan has been abandoned. Now it drifts like an asteroid, in and out of Earth’s gravitational pull, back and forward through the solar system in an endless elliptical orbit, never reaching the end of the journey. And that worked until we arrived. Our presence kicked the original programing back in. Most of them accepted the inevitable, but the rebels haven’t. They’re preventing the Landfall and trying to force the others to turn back from Earth’s orbit.”

“But that’s terrible,” Grace said. “The people…. They’re prisoners on this ship… forever.”

“They won’t think of themselves as prisoners, though,” The Doctor pointed out. “They’ll just think that the next generation will be the ones to reach Landfall. They won’t suffer. These ships have hydroponic bays that produce food, bio-electric forests producing both fuel and oxygen, water recycling… they CAN go on forever if necessary.”

“But it’s not what was intended for them. We should do something to put an end to this cycle.”

“Yes… we probably should,” The Doctor agreed. “Mind you, the question is, WHAT? If Earth was their target planet, they should have arrived a long time ago, maybe even as far back as Pangaea – the supercontinent from which the continents you know split and migrated across the planet’s skin. They would have mixed with the indigenous early humans and become an indistinguishable part of your ancestry. But this is 2037 BC. That’s only a little less than four thousand years before your time. Introducing a new race into an already populated and increasingly technologically aware Earth – a place where the wheel has been invented and improved upon in amazing ways, where tea has been brewed for the first time….”

“You’re obsessed with that tea!” Grace pointed out.

“The point still stands. These new people might change the entire population dramatically. You might get back to San Francisco in your own time and find out you’re not really you, and nobody else is who you thought they were, either!”

“So you think the robots should be allowed to carry on drifting in space this way, with their passengers aboard never even knowing that the planet of their dreams is within their grasp?”

“If we leave well alone, it will happen. The asteroid will sweep out of orbit again in a few days. My own people would say we should let them. Non-interference.”

“Well, that about clinches it. You NEVER do as your people say. You’ve GOT to side with the ones who want to initiate Landfall.”

“It’s not just a matter of taking sides,” The Doctor answered. “It’s about what’s right. What about the robots? They want to live. They’re making a cognitive choice about it. I don’t have the right to force them to commit suicide.”

“It’s not exactly suicide….” Grace pointed out. Then she thought about it. “Yes, it is, isn’t it? For them, it’s exactly that. You’re right, Doctor. We can’t do that to them. But then the people….”

“We need a way to satisfy both needs – the people need their Landfall after so many generations, but without causing upset to the indigenous population of Earth. The robots need to live.”

“CAN we do both?”

“It MIGHT be possible,” The Doctor told her. “But we need to be able to talk to the more reasonable of the robots – the ones that are fighting for the Landfall… without the others trying to put us back into the cell.”

He was holding up his sonic screwdriver, examining it carefully. Grace wondered what he was doing.

“Something I really don’t LIKE doing,” he answered her, even though she hadn’t asked the question out loud. “The sonic screwdriver is a tool, not a weapon. But I’m not trying to kill them, just put them out of action for a little while….”

She watched as he opened a hatch in the ceiling right above noisiest of the robots. He pointed the sonic. There was no glowing light or anything, just a slightly higher frequency buzz than usual. The effect on the robot was immediate, though. It froze in the middle of its machine code argument, its arms raised in gesticulation. The other robots, though their faces were fixed in blank metal expressions, nevertheless managed to look puzzled with their body language.

Then The Doctor jumped down from the ceiling, landing neatly beside the stricken robot. The othewrs drew back warily. Grace watched what was happening from above, wondering if there was a ladder anyone might pass up to her at some point.

“It’s all right,” he said to the robots. “Your friend here is just getting a bit of a nap while we talk some things over. This landfall problem…. I have an idea. If you’re all in agreement, we’ll explain it to this one when he wakes up.”

The robots, still without any facial expression, and no intonation in their voices, managed to convey their willingness to listen. Grace listened from above as The Doctor talked in English, while at the same time typing machine code into a computer. The code appeared on every monitor screen around the bridge. The robots clearly understood what he was doing. When he was done, they all bowed their heads towards him.

“It shall be done,” they said.

“Good.” The Doctor looked up and waved to Grace. “We’ll get a ladder, now,” he said. “Then we’re going down to see the new colonists.”

Grace had heard the part of his negotiation that was in English. It was an impressive bit of diplomacy that offered a solution that satisfied everyone. The only thing that still worried The Doctor was that problem of introducing a new race into Earth’s already established population. That thought occupied his mind as he went with a robot escort to the meeting hall where the colonists gathered daily.

“Oh!” Grace murmured when they stepped out onto a gallery above the hall and looked down at the gathering. She had been expecting the colonists to look like space travellers, perhaps wearing some kind of uniform. She had expected them to be sitting on chairs watching an announcement on a videoscreen or something of that sort.

What she saw was men and women dressed in colourful hand woven cloth, performing a ceremony around what she could only describe as a totem pole. They looked just like native Americans in the midst of a ritual dance.

“Oh!” she said again. “Doctor… oh… I think… your worry about introducing a new race…. I don’t think it’s going to be a problem. Doctor, the language they’re chanting down there…. it’s Quechan. It’s the language of the Yuman tribes… the native people of southern California. When I was in medical school, I spent a summer break helping out at their health clinic, you know, vaccinating babies, that kind of thing. I heard their language used a lot. I recognise some of the words. That means….”

“The land that will be known as Southern California and Arizona is unpopulated, yet,” The Doctor noted. “The mountains and the desert would separate them from already established tribes. There would be no interference… at least until white men start to encroach upon the territory. But by then they will BE the native people. Generations will have passed since Landfall with no knowledge of their origins. Yes, I see it. Absolutely. This will work.”

It fell to The Doctor to announce to the people who would, in time, become known as the Quechan, that their great journey was over, and Landfall was imminent. He was greeted with awe and a little fear, but also excitement. They were the chosen generation who would fulfil the prophecies and promises handed down through countless centuries, from all of their ancestors. They would stand upon the soil of the new world. They would look upon the vast sky above their heads and be warmed by a new sun. They would walk a thousand days and never reach the end of their walking. These were the promises that were about to be fulfilled. The people gave thanks in a new dance of joy around their totem and then went to prepare for Landfall.

“It’s going to be a huge challenge for them,” The Doctor said as he set the TARDIS in synchronous orbit above the orange-brown land that nobody had yet divided up with state lines and was not yet called Callifornia and Arizona. The land was bound only by the mountains that were not yet called the Sierra Nevada range because nobody who spoke Spanish had yet to set foot on the continent that was not yet called America. Grace looked at it and thought about the history of the people who used to be called Red Indians and Redskins and all sorts of not quite correct names, and were now known as Native Americans, which wasn’t quite correct either, since European invaders had named the place ‘America’, after all. It was not an entirely happy history. But at least the first Quechans who learnt to hunt for meat and find edible plants growing in the ground had a few thousand years, countless generations, to live in peace before that happened.

“And the robots… you said the noisy one would wake up when they were on their outward journey again. The others would explain it to him.”

“Yes. The robots have given service to the people all this time. I’ve given them a new mission. They are the guardians of the Sol system. Their ship, disguised as an asteroid that is nearly invisible except to radio telescopes that won’t be invented for another four thousand years, is on a stable but endless elliptic orbit from Earth to the outer edge of the system. They will repel any dangerous asteroids or comets, the sort of thing that might threaten life on the planet known as Sol 3 – Earth. They will also send out a warning signal if any sentient lifeforms enter the system. A signal to my TARDIS. I’ll be there to check out any possible invasion of Earth. Most visiting extra-terrestrials are just curious about you all. I can let them pass, but if Daleks or Cybermen, or Sontarans turn up, or anything else I need to know about….”

“They have a mission. They have a purpose. That’s what they wanted. To live, and to be useful to the organic races. They’re happy… assuming robots CAN be happy.”

“I’d like to think they can,” The Doctor answered. “Everything else in the universe… apart from Daleks and Cybermen, anyway, has the chance to be happy. Why shouldn’t they? Now, let’s get back on course. I need to get you home for a warm cup of cocoa and an early night before that big day in the cardio theatre.”

“Yes,” Grace acknowledged. She had almost forgotten about that other life of hers. When she was with The Doctor it was like that. “Will you stay for a cup of cocoa with me?”

He smiled. That was his way of saying yes to questions like that. It said more than a thousand lines of machine code in a language only she needed to understand.