This was to be Mark's last Transplanetics lecture in the large classroom, his last lecture from old Professor Zollard, one of the pioneers of the new Science. After it he would have a month holiday and then start his work as a Transplaneir operator. As he sat in his push-button revolving cylinder-desk, he realised he would have to wait at least another quarter of an hour for the lecture to start as his Jetule had been early, and Professor Zollard was not noted for his punctuality. He also realised that he was very tired and was looking forward to the month-long holiday which would begin the next day.
Sitting there waiting, he thought back over how he had spent his life. He remembered the time when he was a little boy of five, living with a man and a woman whom he had called his father and mother. He had been happy, very happy, until the day he turned six years old. That was when he was taken away from his parents for the testing process. With many other children, none of whom would ever see their families again, he was studied and examined and tested and experimented on until, at last, when he was seven years old, his future was decided. He was to be a Transplaneir Operator, one of the most skilful, exacting careers available. He went to The School when he was eight years old and, for five years, was given the standard general education required for all children before entering their specialist courses.
When he was thirteen he started learning the basic principles of Transplanetics and the necessary Mathematics. Of course, in those days, the Transplaneir machines were very rudimentary and little was known about the Planes themselves. Even now, Transplanetics was still in its infancy, but enough was known to make it the most important of the large body of New Sciences. For seven years this study had fully occupied, with no rest except for Saturdays and Wednesdays, and a one-week holiday every six months.
Then, at last, as soon as he turned twenty, a wife was selected for him by the Matriputer, a wife who had been thoroughly tested at the age of nine, found to be a perfect partner for a No. 5381, which Mark Burman happened to be, and was brought up and trained in the way all No. 5381 wives should be brought up.
Of all the women suitable for men of the No. 5381 type, Sandra Mellet was found by the Matriputer to be just right for Mark Burman and the two were, therefore, married and then introduced to each other. Before this, Mark had sometimes inwardly rebelled at the thought of the cold mechanical way his wife was found for him, and looked back to the good old days he had read about, when his wife would have been chosen for him by his parents. Of course, such a system made no sense in a society where children lost all contact with their parents after the age of five. In any case, he soon changed his mind the moment he saw her. The Matriputer, of course, had indeed chosen the perfect wife for him. He would be happy to live with her in the modern apartment they had been provided with at the Transplanecentre, having the required number of children and bringing them up until they, in turn, would be taken away at the age of six for their tests and examinations. He had been given a two-week holiday with his wife and was then sent back to The School for the last three years that would complete his education.
After this final lecture, Mark would have his well-earned month-long holiday, with the wonderful wife he loved so much. He daydreamed of her now as the minutes ticked by. Those sparkling blue eyes, that shiny brown hair, that nice little turned-up nose … that rough white beard, that balding head, and those large smiling eyes. Professor Zollard had entered the room. Mark gave him his full attention as he commenced, in his strange foreign accent.
"Today, students, as you know, is our last lecture. You all know your work thoroughly and are ready to begin your careers as Transplaneir Operators in two weeks. But, for now I want you to forget about all you have learnt. I want to take you back through the years to the time when I gave you your very first lecture on Transplanetics, two years after you started your Secondary Education course. You may not be aware of it, but that lecture was recorded at the time. I am now going to play this recording for you, and I want you to imagine you are boys of 15 years of age who are just embarking on the course you have been taking for the last eight years. Students, your first lecture on Transplanetics."
He pressed the switch to operate the Tactoscope, and, as the lights went down, there he was again on the other side of the room, dressed in the same shabby uniform, but looking somewhat younger.
Professor Zollard's image, at the side of the three-dimensional diagram-board, operated a metal lever to draw a long strip of cubes joined together.
"Now, boys," he said, "you are all, I'm sure, familiar with the diagrammatic representation of time, as I have shown it on the board. This represents an endless row of three-dimensional spaces, through which we are journeying, from the left to the right on the diagram, that is, from the past to the future. We appear in one cube for a moment, then we disappear while appearing in the next and continue to do this for our whole journey. It is as if a magnet were pulling us onwards to the right, meaning, of course, to the future. In reality, the cubes are each the size of infinity and, rather than being placed beside each other, they are all occupying the same space. Because of the irresistible force of the imaginary magnet pulling us from past to future, we know we can not travel backwards through time, as we could never produce a force strong enough to resist the force of the magnet. The most we could hope to do is produce an equal force in the opposite direction - left in the diagram, the past in reality. This is not likely for many years to come. As yet we have barely been able to even slow ourselves down a little in time.
"Now you must remember that there are an infinite number of these cubes, and that the time we spend in each one is so small it tends towards zero seconds. Therefore we go through an infinite number of cubes every second. So, we are driven onwards through this infinite number of spaces of infinitesimal time length by a magnetic force pulling us towards the future.
"So far we have the three dimensions of each cube and the fourth dimension, from left to right, which represents time. Let us say that at the moment we are in this cube here." He pointed with the indicator to one of the volumes represented on the diagram-board. "Let us add through this point an entirely different dimension." And he worked the lever to produce a vertical row of cubes perpendicular to the horizontal strip. "This dimension represents one that we had never travelled along until the Transplaneirs were built. We had been pulled in this horizontal direction towards the future but never at right angles to it. Now let us add yet another row of cubes through our chosen block, but this time at right angles to both the rows you already see. He manipulated the lever again and a row appeared stretching horizontally out towards the class and back behind the diagram-board to infinity. Professor Zollard jiggled the lever about rapidly until there appeared on the board a solid block of cubes. The original past-future strip was highlighted in the middle with a darker outline than all the rest. "We continue," he said "to move from past to future, from left to right along that central strip. It is impossible to resist the force of time, but why could we not create a strong enough force to break through the barrier to one of the adjacent rows? It would be at right angles to the irresistible force and we would therefore simply be acted on by a combination of the two forces, enabling us to break through to the lateral dimension while still heading towards the future.
"In this block there are an infinite number of cubes, each one representing an infinite three-dimensional space as we experience it. Of course, all of these blocks are actually occupying the same position in space. All this great mass of cubes you can see is squashed together to make one complete cube, infinite in every possible way, with an infinite number of dimensions, only four of which we were familiar with until the great science of Transplanetics was developed.
With the Transplaneirs we have been able to break through the barriers into different Planes, as we call them, somewhat ironically, as a plane is by definition merely two-dimensional.. All you boys who are sitting in this room now will some day drive these wonderful machines. You will be the Transplaneir operators. It will also be your responsibility to explore some of the many Planes which have been reached, and to try to find ways of breaking through further barriers, thus bringing them within the reach of mankind.
"Now it is time to tell you a little about these Planes. If you moved from one Plane through to a new one you would see absolutely no difference at all, with the sole exception, as far as we know, of our own one. If you left one Plane watching a dog chasing a rabbit, you would see exactly the same chase being continued in the next Plane. In every Plane, the same dog would be chasing the same rabbit, until, of course, man has come onto the scene and, by doing so, alters the normal course of events in that Plane. The difference between our Plane and all the others is that this is the only Plane we know of where Man exists. The reason for this is yet to be explained. Clearly Man is something different from every other species, something alien to the rest of the universe, which has upset the natural order of everything else. If Man did not exist, our own Plane would be exactly the same as every other Plane we have discovered, but the influence of Man has been so great that there is barely any similarity even in the scenery.
"Some of you might ask why all these other Planes are exactly the same in every detail. The answer is really quite obvious. It is simply the fact that every action occurs for a reason. Every action leads to another action, and everything has a specific cause. These different Planes must all have begun aeons ago in exactly the same way. Everything that has happened since has followed a definite pattern of cause and effect. In the instance I gave you, the dog was chasing the rabbit because he was first in a position to see the rabbit, and because the circumstances of the hour or two before had predisposed him to chase the rabbit. Perhaps he was chasing the rabbit because he was hungry. He would be hungry because he had not found anything to eat for a long time and the reason for that would be that his path, his apparently aimless wanderings, had not taken him near the path of food, say other rabbits. This is where the main difficulty comes in. Was it coincidence that he had not seen a rabbit on his travels? The answer is no, as there is no such thing as chance. Now I know that you have learnt in your early Mathematics about the laws of chance and Probability and these laws are true in some ways.
Let us take the example of tossing a coin in the air. You have learnt that the probability that the outcome will be heads is 50%. This is not technically true. It would be more correct to say that the probability that we will choose the right side of the coin is 50%. For the coin will land, not according to chance, but according to a large number of specific factors. Some of these will be, for example, the distance from the coin to the ground, the velocity and angle of projection, the speed and direction of the wind and the revolution of the coin, the nature of the surface of the ground, and so on. In turn, each of these factors depends on another series of specific circumstances. You may ask why all these factors are necessarily constant. You may say, why can't the two men in two different Planes flick the same coin with different velocities. The answer is that the force at which the coin is projected depends mainly on the state of mind of the person, which would be constant in all Planes at that particular moment, as all circumstances leading up to the tossing of the coin must be similar.
"Of course, this example is hypothetical, given that Man exists only on one Plane, as far as we know. But not for long. Most of you probably know that there are plans to send large numbers of people to populate the Planes which we call Numbers 2 and 3. With the new influence of Man, these Planes will rapidly become different from all others and from each other. This proposal is the perfect answer to the world's population problem.
"We used to think we might some day be able to send people to other planets to live, but we now know that this almost impossible task would be unbelievably expensive and very dangerous. Also the people migrating to such planets would probably have to spend their whole life in artificially lighted, covered cities, with a diet consisting mainly of pills.
"All we have to do now is to transport people through the barriers into another Plane, where they can build up a new world. The climate and other conditions would be the same as those they were used to, for they would still be on the same planet. Also they could occasionally visit their home Plane if they wished. They would be quite comfortable in the knowledge that their friends and relatives were still very close to them in terms of space, although on a different Plane.
"Just for a moment, let me return to the subject of Chance. I have said that Chance does not exist, but that everything depends on definite causes. Therefore, you may ask, why can't we predict the future? The answer is, of course, that we just don't know all the factors that are involved, but even if we could tell the future of a person, what was predicted would not be accurate as the prediction itself adds another factor, which, if then taken into account, would generate a further factor, and so on ad infinitum."
The young men were listening patiently. The first time they had heard this lecture, they had understood very little. Now, after many years of study in Circular Mathematics and Transplanetics they knew and understood all that was said.
Very soon afterwards, the image of Professor Zollard finished his talk, and turned off the Tactoscope. "That, pupils," he said, "was the first lecture I ever gave you. It is also the last you will hear from me. For the remaining portion of this lesson I am giving each of you a task to do. For the first time each of you is going to operate a Transplaneir completely by yourself. This should be the first and last time you will be able to do this as the Transplane-laws say that there must be at least two operators during a Transplane trip. We have permission however to give you one final test - that of operating a Transplaneir alone. I will give each of you a short list of Planes you are to visit, and a few instructions which will test your initiative and ability as Operators. The recorder-indicator will give me your results and show me if you succeed in your tasks."
Professor Zollard placed an envelope in each of the sending-slots on the side of his master-desk. A moment later they reappeared, sliding out of slots on each cylinder-desk. Each one was picked up and read by the students whose desks they had reached, and, when Professor Zollard gave the word, all the pupils rose and walked out to the long corridor which led to the enormous training room, where the Transplaneir machines were located.
Mark started his calculations for reaching Plane 3. These were based mainly on the nedominal breadth of the barrier at that time. The breadth of the 1-3 barrier varied from 122 to 158 neids with a time cycle or period of 86 days, 4 hours and 3 seconds. All time cycles were measured from the date of the invention of the Transplaneir. This complicated matters a bit as the cycles did not start at their maximum or minimum nedominal breadth. However, Mark made the calculations in less than a minute, then moved three levers in the appropriate directions and distances, pressed two buttons, turned the starting wheel, then sat back in his seat and waited. It was about thirty seconds before anything happened. Then gradually the room darkened until all was pitch black. Very, very slowly that strange shaky tingling sensation started. Something like a slight electric shock, it rose to a peak, then gradually disappeared, leaving Mark in a perfectly relaxed state. His eyes closed and he saw again the familiar cushion-like shape, like a black diamond lying lengthways with edges curved slightly inwards on a black background. Though it was exactly the same shade of black as the background it was still very well defined in his mind. Now it seemed to tower over him, growing larger and larger, coming closer and closer, then finally engulfing him. As his mind passed slowly through the shape he felt that beautiful sensation experienced by all who travelled from one Plane to another. His body rejoiced in the wonderful freedom of space and time that passed through his soul. He was free. No bonds of space or of time confined him. There he floated, between two Planes, forever, an infinity surrounded by infinity, a mind that covered infinity and knew everything - just a mind. His body was no longer needed. He saw everything, he knew everything - he was everything. Then he shrunk, and was again trapped inside the prison of his body. His mind was small, and he no longer knew everything. He had passed through the barrier from Plane 1 to Plane 3, in what had seemed like an age, but was actually about five seconds.
He opened his eyes. Light came. And there he was in another dimension, on another Plane. He had not moved in space and had not moved far in time, and yet, how far he had gone!
Mark pressed the Temporary Rest Button and closed the safety lock, after glancing quickly at his instructions. He found that he was to ask the leader of the Trebla settlement for a list of any supplies which would need to be replenished. There were not many required as the settlement was now quite well established, and was able to produce most of its own needs itself.
This simple task done, Mark made his way back to the Transplaneir and prepared for the more difficult breakthrough to Plane 44.
The preparations this time took about half an hour, as there were multiple barriers to be crossed. Also, the further out from the Central Plane, the less definite were their periods and nedominals. For these calculations a special guidebook was used, with the most likely measurements shown for each Plane at various points on the time cycle.
At last the work for the second leg of his journey was completed and, after four minutes of pressing buttons and turning levers, Mark sat back again, ready for a longer voyage, which would, however, seem no longer than the last. Again the strange sensation occurred and the black diamond shape with its edges curved inwards loomed up ahead in his mind. Again he passed through that infinite depth of darkness. Then in quick succession some more shapes exactly the same as the first grew in his mind and passed through him, or he through them, until finally he reached his destination, Plane 44.
Mark had some secret instructions for the leader of the small colony on this Plane. This task did not take long and soon he was able to return to the Transplaneir and start his calculations for the difficult journey to Plane 163. Mark studied his guidebook for the most likely nedominal widths and periods of the barriers between the Planes through which he had to pass. As far as he could see, he could reach Plane 109 by continuous flight and would have to take the rest by short jumps as measurements were not definite enough and possibly inaccurate. It was not wise to cross more than one uncertain barrier at a time. Mark thought he should be able to reach plane 162 by this method and then attempt to cross the puzzling barrier that surrounded Plane 163. According to his guidebook the period and maximum measurements of this barrier were unknown.
When Plane 163 was first reached, the barrier was 85 neids in breadth. Since that time, a few months before, the measurements had rapidly decreased to an amazing minimum of only 2.5 neids, and then shot up to over 300 neids, making the six surrounding barriers of Plane 163 the largest ones known. Even then it had probably not reached its maximum. There was some kind of cycle involved here that had yet to be interpreted. One of Mark's tasks was to record the nedomic measurements of the barrier as he passed through it. His second job was to visit a certain spot on the Plane where the scenery was reported by an Operator to be slightly different from the scenery at that point on all the other planes.
By the time Mark reached Plane 162 it was early afternoon. Only a few hours had passed since he had left the lecture room, though it seemed much longer. Now, ahead of him, lay an unknown barrier. Had it reached its maximum and started to wane again, or was the nedominal width still expanding? The greater the nedominal width , the more dangerous the journey would be, although no serious accidents had occurred since the early pioneering days of Transplanetics. The machines were very well built and capable of crossing barriers of over a thousand neids, a capacity which was unlikely to be required, as a width of more than as few hundred neids was a very rare occurrence.
However, Mark was taking no chances. For the first time in his life he turned the little knob labeled "Indefinite". Mark opened a deep drawer and took out an apparatus, which he placed over his head, covering most of his face. There was a small plastic window for his eyes, and a lot of intricate machinery inside the top, above his head.
Mark pressed a button on top of the helmet and then operated a number of dials and levers on the Transplaneir, turned the starting-wheel and he was ready - ready for the unknown barrier which stood before him - ready to be taken to the next dimension - Plane 163.
From a deep blackness he went to a deeper blackness, and from that to an even deeper blackness. Darker than the darkest night, darker than darkness. Then the darkness went and there was nothing. An infinite stretch of nothing.
Mark thought, and the thought spread, filling the void. He thought again. Soon his mind was functioning almost normally, thanks to the "Cap of Consciousness" he was wearing. This device, to be worn only in abnormal circumstances, enabled the user to keep almost full consciousness during a Transplaneir leap across one barrier.
The nothingness of the endless void was real, while the dials were unreal and unimportant shadows in his mind. He needed all his concentration to remember that these insignificant things held his destiny in the numbers that showed faintly, yet legibly, on the very inside of his mind. An indicator, also in his mind, swayed to the right, and he knew he had ten seconds to press a "stop" button which would end the "indefinite" journey. Some of his consciousness slipped away, then a little more, until he knew only one thing. He must press the button. He did not know why. He did not know how. He had no idea where he was, who he was or what he was doing. All he knew was that his finger had to press the button. He willed his finger to carry out this important task. Press the button. The button. Press it. Press the button.
An infinite distance away an indefinable thing did something to another thing. Mark's one thought faded away completely, and he was without any consciousness at all.
When he opened his eyes, Mark found he had reached his destination some minutes earlier. He looked at the nedominal-recorder and gasped with surprise. It couldn't be wrong. The machine was infallible. Yet how could he have travelled 1336 neids? The barrier was probably still increasing as he sat there. How would he get back? Or perhaps it was decreasing already, having reached an unbelievable maximum. Mark shuddered. What if he hadn't used the "indefinite" button and simply set the dials for what would normally be considered a large distance?
However, nothing could be done now. The machine needed a rest after the great strain that had been placed on it, so Mark decided to follow his instructions and investigate the landscape which had been reported to be slightly different from what was expected. Actually Mark was rather sceptical about it as he headed towards the designated spot. It was probably just a case of an explorer who had been crossing a few too many barriers at once. However he had to investigate - perhaps he might find something interesting after all. His destination was a few miles away so he fastened some floaters to his feet and sped away.
Not long afterwards Mark stood, staring at a large rock in the middle of a clearing - a clearing which should not have been there.
There was something different about the rock too. In fact there was something very funny about it. It was moving. It was rising slowly into the air. Mark stared in amazement as it reached a height of about five feet, resting on three thick steel poles protruding from the ground. He moved over to the large hole underneath it and saw, to his astonishment, a flight of concrete-like steps leading down, down, down into the earth.
And then he listened, intently, as he heard footsteps coming up to the surface. Suddenly, there in front of him stood a small creature, very like a man, with a slightly oversized head, but not so much as to look ridiculous, a handsome face, and - those eyes - those clear blue eyes in that slightly oversized head. Mark could see, reflected in the creature's eyes, kindness, love and intelligence far surpassing that of Man.
"Come down," said a pure voice, in perfect English," and don't be afraid. You will not be harmed." Mark stepped forward - and fainted.
"You're all right, Mark. Sorry I had to throw all that water on you, but I had to wake you up."
Mark realised that he was somewhere under the earth. He had been taken down the flight of steps by the small man with the big head.
"How do you know my name?" he inquired.
"Oh, I've just been searching your memory while you slept," explained the creature.
"I see," said Mark, not yet fully awake. "You searched my memory? Who are you anyway?"
"I am Tal, leader of Sevvi."
"What's Sevvi?"
"Sevvi extends a quarter of the way around the earth. It is one of five sectors, each under separate leaders, and also combined under one leader, the Ruler of the Earth. You know a bit about Transplanetics, of course. We have been studying your dimension for some time and have been observing your progress.
"Some of your race have passed through this plane, and have not noticed anything unusual about it, as our whole world is underground, and we work hard to keep the above ground landscape as close as possible to that of the other Planes. According to your people, this is Plane 163. We have known it for a much longer time as Plane 1, or the Central Plane.
"We are also able to travel to different Planes, but not in the same way that you do. We have very little machinery here, apart from food-producers and simple gadgets like the one that lifted the rock at the entrance. There are a few similar entrances throughout …"
"Wait a minute, please. You say you don't have much machinery. Then how did you build all this underground world?"
"All this was built by our ancestors before our race was fully developed. Our civilisation extends under all the world, even under the sea."
"How is that?"
"Our ancestors had enormous machines with which they built large enclosed air-conditioned cities underneath the surface of the earth and sea. Every bit of waste material taken from the earth was translated to another Plane, millions of your 'neids' away. When our race was fully developed we sent all our machines to this Plane, except for a few we could not do without. We no longer needed anything else built, and we had other means of travel. You see, we can travel wherever we like, through space, time and any other dimensions, without using any machines."
"Amazing! But if you have been to our Plane why didn't you let us know of your existence?"
"Well, that's where the catch is. We have been to your Plane many times - as I said, we can travel anywhere - but unfortunately our bodies can't go with us. We have to leave them behind. You see, we are so fully developed that our minds can leave our bodies and go exploring, taking our senses of sight, smell and hearing with us. We can not take our voices off this Plane so we have no way of making our presence known, and very often no need. It is only recently that we have needed to contact you.
"As you know, another of your species passed by our entrance a few days ago, but by the time we reached the entrance he had gone. We know everything that goes on up there, as many of us are there, or our minds at least. Our bodies do not go above the surface very often, as they do not like the sunlight.
"But of course you are finding this hard to digest. You must rest a while. I'll go and tell my wife to get you some afternoon tea. Wait here!"
Mark waited, expecting Tal to stand up and leave, but instead he just sat there, perfectly still. It seemed almost as if he had gone into a trance.
Some minutes passed. Then suddenly, through the doorway, came a woman with a tray of food and drink. She was similar to Tal but with long dark hair and a very pretty face.
"I am Tali," she said, "Tal's wife. You must excuse him. He will be back in a minute. Meanwhile you may eat."
"But Tal's here! … Oh, of course, his body is here but his mind went to get you!"
"Yes. You see, our minds can communicate with each other without needing our bodies. Look! He's coming back now."
"Yes, I'm back, " agreed Tal. "Now, let's eat."
Mark took a small piece of the food he was offered. It was delicious. So was the drink.
"What sort of drink is this?" asked Mark. "It's lovely!"
"Not bad, is it? It's the juice of a type of vegetable we grow here. You can take some of them back with you if you like."
Mark was relieved to hear that. He had been a little afraid that he would have to stay there, though he was certainly not being treated as a prisoner.
"By the way, I wonder if you can tell me about this strange barrier between your Plane and the next, Plane 162. How big is it going to get?"
"It's not just Plane 162. It's all six barriers surrounding this Plane. As I said before, this is the Central Plane. The barriers around it control all the barriers for thousands of dimensions away, and are controlled by an unknown force emanating from this Plane, a force that is thought to have something to do with our creation.
"These six barriers have a time cycle of approximately 150 years."
Mark stood stunned. When he was able to speak he said, hoarsely, "Then how will I ever get back?"
"Your machines are capable of crossing nearly two thousand neids, though you have been taught otherwise. If you leave today you have a fair chance of returning safely. You may either risk it, or live here for the rest of your life. It is your choice, but it is important to your people that you return, as we have a message for them. Otherwise we would not have shown ourselves."
"Why? What is this vitally important message?"
"It's in this envelope. You must give this to the head of the Transplanetics Department as soon as possible. We will know whether you make it or not. If not, we can only hope that some one else will reach us in a very strong Transplaneir. Otherwise - I have to tell you the truth - your race is doomed. You would not understand, but it has something to do with a miscalculation your designers made in the construction of your Transplaneirs. You have only two months to destroy the first three of them, before their propelling forces cause devastation throughout your whole world… Let me know your decision."
"Of course," replied Mark. "I have no choice. I will do my best to get back to my own Plane and deliver this letter."
"The letter, for your information, contains instructions for safely dismantling the machines, and the dates on which the others must be destroyed. It also shows where the mistake was made so that it can be avoided in new machines.
"The safest time for you to leave will be in about forty minutes. You must let your Transplaneir rest a little longer, but you must remember that the barrier is growing wider and wider, nedominally that is. Its maximum is over a million neids, so wide that even we would not be able to pass through it."
"I will take your advice and leave in forty minutes. I have a chance to save the human race, and I am confident that I will succeed."
"So am I, but I can see in your mind that you are afraid. Come! For the next half an hour I will show you around this city, Milwa, the capital of Sevvi."
Mark and Tal left Tali, to go on a quick tour around the underground city. Mark was shown sights that he could never have imagined. It was beautiful. He was surprised that anything underground could be so pleasant to look at or live in. All around him he saw the calm, happy people wandering about, and some of them standing perfectly still. These, he knew, might actually be wandering anywhere on the planet, or the rest of the universe, the dimensions, or even time.
"How could they?" wondered Mark. "We have been taught that it is impossible to travel through time."
"I can hear what you are thinking," said Tal. "It is impossible for you to travel back through time, but not for us. The irresistible force pulling our bodies towards the future can have no effect on our minds. We are free to explore the distant past, but we can not go into the future. When we return from the past we can only get back to the exact moment when we left our bodies or any time earlier than that. We are unable to project even our minds into the future. With that one restriction, we are free to explore as we wish - other Planes, other planets. Or we can go to another part of the country and instruct our bodies to follow us there, we can … But, you know, some day your race will do these things too, if you survive that long. In thousands of years the human race should be perfectly developed as we are. You have not seen much of our world in your short stay, but I think you have seen enough to satisfy you that it is a superior way of life."
"Yes, I have. It's - it's perfection."
"And it's partly up to you, Mark. You may be able to save mankind. I would advise you to leave now. You have five minutes to get back to your Transplaneir if you want to leave at the safest time."
By this time the two had arrived at the bottom of the flight of steps leading up to the entrance through which Mark had been carried not long before.
"Go back to your Transplaneir. You will find me waiting there for you."
"How…?"
"As I am a leader I am allowed to have two bodies. I instructed my other body to go to your machine some time ago. I will be occupying that body by the time you get there."
It was true. When Mark arrived he saw Tal, looking slightly different, but still recognisable as Tal.
"Greetings, Mark. I am here as promised."
"How did you arrange to have two bodies?" asked Mark.
"Let me explain. Leadership here is hereditary, so when my parents wanted a child they simply had twins, which are now my two bodies. When we were three years old, the age at which the mind is able to leave the body, our minds were joined together to make one, which can occupy either of the two bodies or none at all, at any time. I hope you are not shocked. I realise that it is against the law to have twins in your society. It's the same here too, except for leaders, who always have twins. And now it is time for you to leave."
Mark pressed the "indefinite" button and made the other preparations to leave. He put the Cap of Consciousness on his head and turned it on fully.
"I'm ready now," he said. "But before I go, may I ask you one more question?"
"Yes, certainly. What is it?"
"Can you tell me how the human race began?"
Tal's face fell and wore a painful expression. Mark saw it was not a good question to ask. "I - I prefer not to tell you that," Tal said quietly.
Mark tried not to show his surprise and disappointment. "All right," he said. "I must go now."
Tal tried to bring back his smile. "Goodbye," he said. "Your people are depending on you."
"Goodbye, Tal." Mark turned the starting wheel.
Tal watched as the Transplaneir faded away before his eyes. "Goodbye my friend," he thought. "I hope you make it."
800 neids he had travelled already.
It was much faster when he was fully awake.
900 neids... 1,000 neids.
This was the danger level, he had been told. Now he knew better.
It was a little longer before 1,100 showed on the indicator. The machine was slowing down.
Mark picked up one of the strange vegetables he had been given, pushed it up the front of his helmet and ate it.
"Delicious," he thought. "I'll give some to the food scientists to study."
1,200 neids.
Mark had felt faint, but the vegetable had revived him. He took a mental note of that.
1,300 neids. Getting slower. Getting darker.
Mark quickly brought another of the vegetables to his mouth. The light in the machine had not changed. It was only in his mind.
1,400 neids.
"How much further?" he thought. He couldn't keep his consciousness much longer. Then he heard - "Snap!"
There was deadly silence.
The number on the indicator stayed at 1,468.
The machine went dark.
Everything went dark.
Mark tried to scream, but he couldn't. The Transplaneir had stopped in the middle of infinity.
Mark sat perfectly still. He could not move, for he was caught between two Planes, and between two intervals of time. In relation to everything else, Mark Burman ceased to exist at that moment. In relation to himself, he was still there; he would be there forever, existing in the same place, in the same position, in the same state of mind, unfortunately an unpleasant one. He was no longer acted on by the past-future force. His machine had found a neutral point in the middle of nowhere. He lived for one more instant, an instant which lasted for ever.
In the meantime, two months later, the world of humans ended.