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  In other words, let me see how smart you are. Rebka took the documents and skimmed them in silence for a minute or two. He was not sure what the test was, but he did not want to fail it. "These all appear to be in the correct official format," he said at last.

  "You see nothing unusual in them at all?"

  "Well, perhaps in the diversity of the applicants. Do you often have visit requests from outside the Dobelle system?"

  "Very seldom." Perry was nodding in grudging respect. "Now we get four requests, Captain, in one day. All want to visit Opal and Quake. Individuals from the three major groups, plus a member of an Alliance council. Do you know how many visitors a year we usually get to Dobelle? Maybe fifty—and they all come from our people, worlds in the Phemus Circle. And nobody ever wants to go to Quake."

  Max Perry picked up the folder again. Apparently Rebka had met some initial acceptance criterion, because Perry's manner had lost a little of its stiffness. "Look at this one. It's from a Cecropian, for God's sake. No one on Dobelle has ever seen a live Cecropian. I haven't seen one myself. No one here knows how to communicate with one."

  "Don't worry about that." Rebka focused again on the sheets in front of him. "She'll have her own interpreter. But you're right. If you get only fifty a year, four in a day is way outside statistical limits." And you haven't said it to me, he thought, but as far as you're concerned it's five in a day, isn't it? These requests arrived at the same time I did. So as far as you are concerned, I'm just another outsider. "So what do they all want, Commander? I didn't read their reasons."

  "Different things. This one"—Perry poked at the page with an emaciated finger "—just came in. Did you ever hear of a man called Julius Graves? He represents the Fourth Alliance Ethical Council, and according to this he wants to come to Opal to investigate a case of multiple murder, somehow involving twins from Shasta."

  "Rich world, Shasta. A long way from Dobelle, in more ways than one."

  "But if he wants to, according to the way I read the regulations, he can overrule anything that we say locally."

  "Overrule us, or anyone else on Dobelle." Rebka took the document from Perry. "I never heard of Julius Graves, but the ethical councils carry the weight of all the groups. He'll be a hard man to argue with."

  "And he doesn't say why he's coming here!"

  "He doesn't have to." Rebka looked again at the application. "In his case, this request is a formality. If he wants to come, no one can stop him. What about the others, though? Why do they want to go to Quake?"

  "Atvar H'sial—that's the Cecropian—says her specialty is the evolution of organisms under extreme environmental stress. Quake certainly qualifies. She says she wants to go there and see how the native life-forms adapt during Summertide."

  "She's traveling alone?"

  "No. With someone or something called J'merlia. A Lo'tfian."

  "Okay, that'll be her interpreter. The Lo'tfians are another life-form from the Cecropia Federation. Who else?"

  "Another female, Darya Lang from the Fourth Alliance."

  "Human?"

  "I assume so. She claims to be interested in seeing Builder artifacts."

  "I thought there was only one in the Dobelle system."

  "There is. The Umbilical. Darya Lang wants to take a look at it."

  "She doesn't have to go down to Quake to do that."

  "She says she wants to see how the Umbilical is tethered at the Quake end. She has a point there. No one has ever understood how the Builders arranged for its retraction to space at Summertide. Her story is plausible. Believe it if you want to."

  Perry's tone of voice made it clear that he did not. It occurred to Rebka that they had at least one thing in common—their cynicism.

  "And then there's Louis Nenda," Perry went on. "From the Zardalu Communion. When did you last hear from them?"

  "When they had their last skirmish with the Alliance. What's he say he wants?"

  "He doesn't bother to tell us in detail, but it's something about being interested in studying new physical forces. He wants to investigate the land tides on Quake during Summertide. And then there's a footnote, talking about the theory of the stability of biospheres, as it applies to Quake and Opal. Oh, and Nenda has a Hymenopt along with him, as a pet. That's another first. The only Hymenopts anyone has ever seen on Opal are stuffed ones in the Species Museum. Add them all up, Captain, and what do you get?"

  Rebka did not answer that. Unless all the records on Perry were false, there was a subtle, flexible intelligence hiding behind those pale, mournful eyes. Rebka did not believe for a moment that Perry was asking advice because he thought he needed it. He was feeling out Rebka himself, probing the other man's intuition and sense of balance.

  "When do they request arrival?"

  "According to this, Darya Lang cleared the last Bose Node three days ago. That means she's on final subluminal approach to Starside Port. Landing request could come anytime. The rest of them are maybe a few days away."

  "What do you recommend we do?"

  "I'll tell you what I recommend we don't do." For the first time, emotion appeared on Max Perry's thin face. "We can let them visit Opal—though that's going to be no joke this Summertide—but we don't, under any circumstances, let them set foot on Quake."

  Which means, Rebka thought, that my instinct back on Starside was spot on. If I'm going to find out what keeps Max Perry on Dobelle, I'll probably have to do exactly that: visit Quake, at Summertide. Well, what the hell. It can't be any more dangerous than the descent into Paradox. But let's test things here a little bit more before we jump too far.

  "I'm not convinced of what you say," he replied, and watched apprehension flicker in Perry's pale eyes. "People are coming a long way to see Quake. They'll be willing to pay Dobelle a lot for the privilege, and this system needs all the credit it can get. Before we deny access, I want to talk at least to Darya Lang. And I think I may need to see the surface of Quake close to Summertide for myself—soon."

  Quake close to Summertide. At those words another expression appeared on Max Perry's face. Sorrow. Guilt. Even longing? It could be any of them. Rebka wished he knew the other man better. Perry's countenance surely revealed the answers to a hundred questions—to someone who knew how to read it.

  CHAPTER 3

  Summertide

  minus thirty-three.

  Hans Rebka had arrived on Dobelle disoriented and angry. Darya Lang, following his subluminal path just three days later on her run from the final Bose Transition Point to the Opal spaceport, did not have room for anger.

  She was nervous; more than nervous, she was scared.

  For more than half her life she had been a research scientist, an archeologist whose mind was most comfortable seven million years in the past. She had performed the most complete survey of Builder artifacts, locating, listing, comparing, and cataloging every one so far discovered in Fourth Alliance territory, and noting the precise times of any changes in their historical appearance or apparent function. But she had done all that passively, from the tranquil harbor of her research office on Sentinel Gate. She might know by heart the coordinates of the twelve hundred-odd artifacts scattered through the whole spiral arm, and she could reel off the current state of knowledge concerning each one. But other than the Sentinel, whose shining bulk was visible from the surface of her home planet, she had never seen one.

  And now she was approaching Dobelle—when no one else had even wanted her to go.

  "Why shouldn't I go?" she had asked when the Committee of the Fourth Alliance on Miranda sent their representative to her. She was trembling with tension and annoyance. "The anomaly is mine, if it's anyone's. I discovered it."

  "That is true." Legate Pereira was a small, patient woman with nut-brown skin and golden eyes. She did not appear intimidating, but Darya Lang found it hard to face her. "And since you reported it, we have confirmed it for every Artifact. No one is trying to deny you full credit for your discovery. And we all admit that you are
our expert on the Builders, and are most knowledgeable about their technology—"

  "No one understands Builder technology!" Even in her irritation, Darya could not let that pass.

  "Most is a comparative term. No one in the Alliance knows more. Since, I repeat, you are most knowledgeable about the technology of the Builders, you are clearly the best-qualified individual to pursue the anomaly's significance." The woman's voice became more gentle. "But at the same time, Professor Lang, you must admit that you have little experience of interstellar travel."

  "I have none, and you know it. But everyone, from you to my house-uncle Matra, tells me that interstellar travel offers negligible risk."

  The legate sighed. "Professor, it is not the travel we question. Look around you. What do you see?"

  Darya raised her head and surveyed the garden. Flowers, vines, trees, the cooing birds, the last rays of evening sunlight throwing dusty shafts of light through the trellis of the bower . . . It was all normal. What was she supposed to see?

  "Everything looks fine."

  "It is fine. That is my point. You have lived all your life on Sentinel Gate, and this is a garden world. One of the finest, richest, most beautiful planets that we know—far nicer than Miranda, where I live. But you are proposing to go to Quake. To nowhere. To a dingy, dirty, dismal, dangerous world, in the wild hope that you will find there new evidence of the Builders. Can you give me one reason for thinking that Quake has such potential?"

  "You know the answer. My discovery provides that reason."

  "A statistical anomaly. Do you want to endure misery and discomfort for the sake of statistics?"

  "Of course I don't." Darya felt that the other woman was talking down to her, and that was the one thing she could not stand. "No one wants discomfort. Legate Pereira, you admit that no one in the Fourth Alliance has more knowledge of the Builders than I do. Suppose I do not go, and someone else does, and whoever goes in my place fails for lack of knowledge where I might have succeeded. Do you think that I could ever forgive myself?"

  Instead of replying, Pereira went to the window and beckoned Darya Lang to her side. She pointed into the slowly darkening sky. The Sentinel gleamed close to the horizon, a shining and striated sphere two hundred million kilometers away and a million kilometers across.

  "Suppose I told you that I knew a way to break in through the Sentinel's protective shield and to explore the Pyramid at the center. Would you go with me?"

  "Of course. I've studied the Sentinel since I was a child. If I'm right, the Pyramid could contain a library for the Builder sciences—maybe their history, too. But no one knows how to break the shield. We have been trying for a thousand years."

  "But suppose we could crack it."

  "Then I would want to go."

  "And suppose it involved danger and discomfort?"

  "I would still want to go."

  The legate nodded and sat in silence for a few seconds as the darkness deepened. "Very well,"she said at last. "Professor Lang, you are said to be a logical person, and I like to think that I am, too. If you are willing to run the risks of the Sentinel's shield, and those are unknown risks, then you have a right to endure the lesser risks of Quake. As for travel to the Dobelle system, we humans built the Bose Drive, and we understand exactly how it works. We know how to employ the Bose Network. The experience is frightening at first, but the danger is small. And perhaps if you can use that Network to explore the statistical anomaly that you alone discovered, it will finally provide the tool you need to crack the secret of the Sentinel. I cannot deny that chain of logic. You have the right to make the journey. I will approve your travel request."

  "Thank you, Legate Pereira." With the victory, Darya felt a chill that was not caused by the night air. She was passing from pleasant theory to commitment.

  "But there is one other thing," Pereira's voice sharpened. "I trust that you have not told anyone outside the Alliance about your discovery of the anomaly?"

  "No. Not a person. I sent it only through regular reporting channels. There is no one else here who would care to hear about it, and I wanted—"

  "Good. Be sure you keep it that way. For your information, the anomaly is now to be treated as an official secret of the Fourth Alliance."

  "Secret! But anyone could perform the same analysis that I did. Why . . ." Lang subsided. If she said that anyone could do the work, she might lose her claim to the anomaly—and the trip to Quake.

  The legate stared at her soberly and finally nodded. "Remember, you are about to embark on a journey of more than seven hundred light-years, beyond the borders of the Alliance. In some ways I envy you. It is a journey more than I have ever made. I have nothing more to say, except to give you my good wishes for a safe trip and a successful mission."

  Darya could hardly believe that she had won, after weeks of red tape and dithering from the authorities of the Fourth Alliance. And the perils of the Bose Drive had indeed faded, once she was on her way and made her initial step through the Network. The first Transistion was disconcerting, not for the feelings that it introduced but for their absence. The Transition was instantaneous and imperceptible, and that did not seem right. The human brain required some notice that it and the ship that carried it had been transported across a hundred light-years or more. Perhaps a slight shock, Darya thought; a little nausea, maybe, or some feeling of disorientation.

  Then at the second and third Transitions that concern vanished, just as Legate Pereira had promised. Darya could take the mysteries of the Bose Drive for granted.

  But what did not decrease was her own feeling of inadequacy. She was a bad liar; she always had been. The Dobelle system contained just one structure that dated back to the Builders: the Umbilical. And that was a minor artifact, one whose operations were self-evident even if the controls that governed it remained mysterious. She would never have made so long a journey merely to look at the Umbilical. No one would. And yet that was the Alliance's official rationale for her visit.

  Someone was going to ask her why she had done so odd a thing; she just knew it. And nothing in half a lifetime of research work had taught her how to fake things. Her face would give her away.

  The sight of Dobelle eased her uneasiness a little. In a universe that she saw as populated by the miracles of the Builders, here was a natural wonder to rival them. Forty or fifty million years earlier the planetary doublet of Quake and Opal had orbited the star Mandel in a near-circular path. That orbit had been stable for billions of years, resisting the gravitational tugs of Mandel's small and remote binary-system partner, Amaranth, and of its two great gas-giant planets, moving in their eccentric orbits five and seven hundred million kilometers farther out. The environment had been tranquil on both members of the Dobelle planetary pair, until a close encounter of the two gas-giants had thrown one of them into a grazing swing-by of Mandel. That unnamed stranger had emerged from its sun-skimming trajectory with a modified path that took it clear out of the stellar system and into the void.

  That would have been the end of the story—except that Dobelle lay in the stranger's exit route. The gas-giant had done a complex dance about the doublet planet, moving Quake and Opal closer together while changing their combined orbit to one with a periastron that skimmed much closer to Mandel. Then the stranger had vanished into history. Only Dobelle and the gas-giant called Gargantua remained, their still-changing orbital elements allowing an accurate reconstruction of past events.

  Summertide, Dobelle's time of closest approach to Mandel, was just a couple of weeks away. It would be a time, if Darya Lang's analysis was correct, of great significance in the spiral arm. And also in her own life. Her theories would at last be proved true.

  Or false.

  She went to the port and watched as the ship approached Dobelle. Opal and Quake whirled dizzily around each other in a mad dance, spinning three full turns in a standard day. She could actually see their motion. However, speed was all relative. The ship's rendezvous with the landin
g field on Opal's Starside sounded difficult, but it was a trivial problem for the navigation computers that would make the rendezvous.

  The problems would come not from there, but from the humans who wanted to greet her. The tone of the message permitting her entry to Opal sounded ominous. "Provide the full identification of your sponsor. State in full the proposed length of stay. Give details of expected findings. Explain why the time of your requested visit is critical. Say just why you wish to visit Quake. Provide credit information or nonrefundable advance payment. Signed, Maxwell Perry, Commander."

  Were the immigration officials on Opal so hostile to every offworld visitor? Or was her paranoia not paranoia at all, but a well-merited uneasiness?

  She was still standing by the port as the ship began its final approach. They were coming in from the direction of Mandel, and she had a fine sunlit view of the doublet. She knew that Opal was only slightly larger than Quake—5,600 kilometers mean radius, compared with Quake's 5,100—but the human eye insisted otherwise. The cloud-covered iridescent ball of Opal, slightly egg-shaped and with its long axis pointing always to its sister world, loomed large. The darker, smaller ovoid of Quake brooded next to it, a smooth-polished heliotrope against the brighter gemstone of its partner. Opal was featureless, but the surface of Quake was full of texture, stippled with patches of deep purple and darkest green. She tried to make out the thread of the Umbilical, but from that distance it was invisible.

  Entry to the Dobelle system offered no options. There was only one spaceport, set close to the middle of Opal's Starside hemisphere. There was no spaceport of any kind on Quake. According to her reference texts, safe access to Quake came only via Opal.

  Safe access to Quake?

  A nice idea, but Darya recalled what she had read of Quake and of Summertide. Maybe the reference texts needed to find different words . . . at least at this time of the year.

  The reference files of the Fourth Alliance had even fewer good things to say than Legate Pereira about the worlds controlled by the Phemus Circle. "Remote . . . impoverished . . . backward . . . thinly populated . . . barbaric."