Her fierce, bold candor reminded him so much of poor, dead Tamora. Perhaps she would leave Cas for him; perhaps there were other women like her. In the swooning excitement of finding his people, he had forgotten his sweetheart, Derev, and the fervent promises they had made to each other before he had set out on the long road which had at last led him here.
Cas said, “The ship hasn’t been to Confluence for generations and generations. How could he come from there?”
Yama tried to explain.
The fastest way to travel from one point to another was in a straight line—or rather, over the long distances between stars, in a curved geodesic, for the mass of the Universe distorted its own space. But within the vacuum of space were holes smaller than the particles which made up atoms. As small as the smallest possible measurement, the holes appeared and disappeared in an instant, a constant, unperceived seething of energies that continually canceled themselves out. The holes had two mouths, and the space that tunneled between the mouths was compressed so that the distance between them was shorter inside the tunnel than outside it. The Preservers had found a way to grab the mouths of certain of these holes, to stabilize and widen them.
Bryn nodded. “The ship uses the shortcuts to get from world to world without traveling. It also uses them to replenish its air and water. You came out in one of the cisterns. Lucky for you it was one that isn’t used anymore, or you would have drowned. But I guess most of them aren’t used now. The crew is pretty skimpy these days.”
Cas was doing pushups as relentlessly as a machine. Sweat gleamed on his bare, muscular arms, pooled between the cords on his neck. Without pausing, he said, “All this is useless stuff. We don’t need to know anything outside the ship.”
“Let him tell all of it,” Wery said. “You never know when something might have a use.”
“She’s right,” Bryn said. “Set on, lad. Finish your story.”
The Preservers had constructed an intricate network of shortcuts between every star in the Galaxy, but the shortcuts could link points in time as well as space. It was done by fixing one mouth of a shortcut to a ship capable of traveling at speeds close to that of light itself. In the realm of light there was no time; or rather, there was a single endless moment which encompassed the beginning and the end of the Universe. As the ship carrying the shortcut mouth approached that unreachable realm, so time stretched about it; while only a few years passed aboard the ship, many more passed in the rest of the Universe. When the ship returned to its starting point, the two mouths of the shortcut now joined regions of space which were separated by the time debt built up during the journey. Someone passing through the mouth of the shortcut which had traveled with the ship would exit from the mouth which had remained where it was, and travel back to the time when the ship’s journey had begun. But they could not return by the same route, because their journey altered the past.
Yama drew diagrams in the dust, prompted by the remains of the Shadow, which was able to filter the vast store of knowledge he had taken from Dr. Dismas’s paramour. As Yama explained his story, he came to understand just what he had done.
The Preservers had cloned certain of the shortcuts, so that one mouth led to many different destinations, determined by slight changes in the potential energy of whatever entered. Aided by the Gatekeeper, Yama had fallen through the mouth of one of these cloned shortcuts, but he did not know where and when he had emerged. He knew only that his wish had been granted: he had been sent to his people.
Yama understood all about cloning, for it was how meat and work animals were bred, but he had to explain it several times before Wery understood. The notion disgusted her, and Bryn was amused by her disgust. “There are many different ways of living,” he said. “That’s why these rooms are all so different, because the passengers were once many different kinds of people.”
“They were all bugs,” Cas said indifferently. He was sitting on his haunches by the door now, polishing a bone dagger. “And we kill bugs.”
“Some bugs are the stock species from which the Preservers made people,” Bryn said. “Although I admit that there’s a bigger difference there than between child and man.”
“Bugs are bugs,” Cas said. “Kill ’em or be killed. Some are harder to kill, that’s all.”
“And you can eat some but not others,” Wery said.
Yama said again, “Because I fell through one of the cloned shortcuts, I do not know where I am.”
“On the ship, of course,” Wery said. “Somewhere about the waist, in an outer deck.”
“He means he doesn’t know if this is his past or his future,” Bryn said.
Bryn knew more about Confluence than the other two, but knew nothing of Ys or the Age of Insurrection, or even of the Sirdar, who had ruled Confluence when it was newly made. His people had been on the ship a long time; Yama suspected that their ancestors had fled here, or refused to leave once the construction of Confluence had been completed. They had been rebels, like the feral machines or Tibor’s ancestors.
Yama said, “I think this must be somewhere in the past. The star-sailors I met knew about my bloodline, but believed that it had died out long ago.”
Wery said with sudden anger, “We will destroy the regulators! They are only machines. They are as stupid as emmets.”
“Emmets have the run of parts of the ship,” Bryn said. “Intelligence is not necessarily a survival trait.”
“Then you cannot control these regulators?” Yama was surprised. He had supposed that all of his bloodline would be able to control machines, but it seemed that things were different on the ship. Wery had not been able to make the floor stuff flow apart, and even he had not been able to touch the minds of the things which had chased him in the cistern. He said, “I suppose that the machines here are not the same as the machines on Confluence.”
“Some say that we controlled the regulators once,” Bryn said. The old man seemed amused. “Maybe we still do, on other ships. It’s bad luck you arrived here.”
Cas said unexpectedly, “There is only one ship, Bryn. It loops through time and sometimes meets itself.”
Bryn said, “Only one ship in our universe, yes, but perhaps there are many universes, eh? A universe takes only one road, but if a man retraces his steps he cannot then return to the place from which he started. For the road splits at the place he traveled back to, and he must travel down the new road. It stops a man killing his grandfather and returning to find himself without existence.”
“Perhaps his grandfather was only the husband of his grandmother,” Cas said slowly, “and not his sire.”
Bryn tugged on his beard in vexation. “His grandmother then! You are an infuriatingly literal man, Cas. I only make a fancy to illustrate a point. There are as many universes as there are travelers. In many we live on into our new mate’s time, perhaps, but not in the time he came from.”
Yama nodded. “Then I would not have had to come here to look for you.”
Bryn said, “The problem is that you can go back to your future but not by retracing the same path, and so it will not be the place from which you started.”
Cas said sulkily, “We’ve stayed here too long, and all this talk is making my head hurt. Why should what one man does cause a new universe?”
“It is no easy thing, to travel back through time,” Bryn said. “But you are right. We should not stay here too long. The regulators might notice the change in carbon dioxide concentration.”
“I have good ventilation,” the room said.
“When I need advice from you,” Bryn said, “I will ask for it. Do your synthesizers still work?”
“Of course, but they are not suitable for your bloodline. I will have to change the settings.”