a very young race: The mother planet offered no more than thirty thousand or forty thousand years of past that had the richness and complexity he sought, and beyond that lay nothing but stray scraps of bone, scatterings of stone tools, the charred ashes of ancient hearths.

  So he had gone out into the galaxy again, digging on worlds beyond the

  Erthuma sphere. At least ten thousand of the worlds of the galaxy had evolved intelligent lifeforms. Only a relative handful of those had gone on to develop technological civilizations, and some of those were extinct: dead by their own hands, so it would appear. Of the survivors, only five, before the Erthumoi, had reached the level of interstellar travel. It was not generally thought that any of the extinct races had succeeded in traveling beyond their own solar systems. A widely held theory argued that there was a critical technological threshold that every race had to pass; the ability to achieve self-destruction invariably came sooner than the ability to attain interstellar flight, and only those races able to master their own self-destructive impulses would last long enough to master the mysteries of hyperspace travel. Many had not.

  Wing-Marra had probed the ruins of dead alien civilizations in a dozen

  different star systems. But they too were disappointing to someone seeking vivid and immediate insight into the look and texture of the distant past. Even in the best preserved of them, not much had withstood the inroads of time: a faint line of stone foundations here, an empty burial vault there, some shattered walls, a battered fragment or two of strange jewelry, perhaps a bit of some unfamiliar and unrecognizable fossil, and not much more. That was all that remained. The youngest of those lost civilizations was one hundred thousand Galactic Standard Years old, according to his dating instruments; the oldest was five times as ancient as that. Mere traces, outlines in the sand.

  But now--on a world where no one could have lived for hundreds of millions of years-

  A city? A complete city, with a discernible street plan and buildings still so intact, after whole geological eras, that roofs still remained and the number of stories could be

  counted? No, that was archaeological nonsense, WingMarra thought. Whatever lay out there on that dead plain, it could not possibly be a settlement that went back to a time when this world still had air and water and vegetation. But what, then? Perhaps, in the stillness and void of this lifeless moon, the familiar forces of erosion would not operate as they did elsewhere, and whatever was built here would remain through all the ages, undecayed. Why would anyone bother, though, to build a fair-sized city on so absolutely inhospitable a place as this world had become once its atmosphere had fled? And who would have done it? Norte of the Five Races, that seemed certain. And surely not Erthumoi.

  A seventh galactic race, unknown to all the others?

  It had to be.

  It could not be.

  This makes no sense, Wing-Marra thought. None whatsoever.

  "What are you thinking?" Sanoclaro asked.

  "A lot of things," said Wing-Marra. "But I don't have enough information.

  Do you know what we need to do now? We need to get into our buggies and ride over across there to take a close look at whatever it is that the Crotonites don't want us to see."

  It was, of course, an outrageous thing to be doing. The ground vehicles were equipped with weaponry, and both Wing-Marra and Murry-Balff were carrying hand-model blasters, which were not uncommon items of male ornamental dress on their home world. The Locrians, too, were armed. But in all the cycles of his life Wing-Marra had never once had occasion to use his blaster against another living creature, and he doubted that Murry-Balff had either. As for using it against a member of one of the other galactic races-no, no, it was unthinkable for a member of one race to injure a member of another.

  He was counting on the fact that the Crotonites were likely to feel the same way.

  Besides, this solar system was unclaimed. If the Crotonites

  had taken the trouble to claim it, they could have closed both Ae second planet and its moon to all other races, and backed that up, if necessary, by force. But they had filed no claim. Whether they had chosen that course for some unfathomable sneaky Crotonite reason or simply because they had been too confident that no other race would find this place was something Wing-Marra did not know. Either way, as things stood, they had no legal right to bar anyone else from landing here.

  They could, naturally, keep trespassers from entering any base they had established themselves. But Wing-Marra had no intention of going anywhere near the Crotonite base. All he wanted to inspect was that big empty place out on the bed of the vanished lunar sea. That was no Crotonite base, was it? That was simply an empty place. How could they stop him from driving right up to it? From peering in? From entering it, if he could?

  11ey would have to admit that there was something there, after all, before they could keep him from trying to look at it.

  I At first, it seemed as though the Locrians would not buy any of his reasoning and were going to refuse to accompany him into the plain. They were afraid of some violation of Crotonite territorial rights that would lead to big political trouble. The Naxian, too, was uneasy about going along. Naxians, because of their keen intuitive sense of what might be going on in any organism's mind, were usually confident of their ability to handle themselves in all sorts of bothersome situations. But Blue Sphere, like the Locrians, indicated that it-she would just as soon stay away from the Crotonite outpost.

  Wing-Marra was unhappy about that. He wanted the Locrians and the Naxian along for a show of solidaritythe Crotonites were less likely to commit some hostile act if they saw that they'd be stiffing up trouble with three of the Six Races at once--and also he valued Naxian intuition and Locrian cold-blooded intellectuality. But they would not give in.

  "Very well," Wing-Marra said finally. "We'll just have to go without you,

  I guess."

  Which broke the impasse, for the Locrians did not trust their Erthuma partners sufficiently to want them to get first look at the enigma on the plain without them, and Blue Sphere, although it-she plainly suspected that Wing-Marra was bluffing, apparently did not want to take the risk that he was crazy enough to mean what he said. So in the end they all went: a tri-species expedition, setting out in two ground vehicles across the hard

  flat limestone floor of the ancient dry sea.

  They were still twenty kilometers or so from the zone of mystery when Eslane Ree pointed out a Crotonite landcrawler coming up on their left. "Everyone into defensive mode," Wing-Marra ordered. "All weaponry armed and ready, but don't get overanxious. Let's just see what they do."

  What the Crotonites did was to swing into a path parallel to theirs at a distance of perhaps half a kilometer, and ride alongside them. A little while later, a second Crotonite vehicle took up the same escort position on the right. Then a third appeared, hanging back to the rear. All dime maintained constant distances from the Erthuma vehicles as they traveled over the plain.

  "The bats watch us, and we watch the bats," WingMarra said. "And neither

  side makes the first move. All right. We wait and see, and so do they. How

  far are we from the edge of the zone, Murry-Blaff?"

  "Seven hundred meters."

  "Well, we'll have some answers pretty soon."

  "Here," MurTy-Balff said. "This is it."

  Wing-Marra signaled and the caravan came to a halt. They seemed to be in the middle of nowhere. Behind diem, far behind, lay the mountains and their camp, and some distance off to the soudi the Crotonite camp. Ahead of them, stretching out almost endlessly, was the bright, chalky, almost featureless plain that once had been the floor of a prehistoric ocean. The green second world, hanging overhead, seemed closer than ever, a massive, looming weight; and its brilliant light cast an eerie, chilling glow.

  Right in front of us, Wing-Marra thought, is a city that may be half a billion years old. And we can't see a damned thing.

  "Here come the Crotonites," Eslane Ree said.

  "Yes. I'm aware of them. Let's get out and sniff around a little. "

  He was the first out of the vehicle. After a moment, one of the Locrians jumped out also, and then the other. Sanoclaro and Eslane Ree followed. Murry-Balff remained with his instruments. Blue Sphere, looking fidgety and troubled, stayed in the vehicle also. Wing-Marra beckoned to it-her to get out. Murry-Balff could do his work from the vehicle, if he wanted to, but Wing-Marra needed the Naxian by his side.

  He took a few steps forward, wondering if he would feel resistance. But there was nothing. Nothing at all.

  "Am I near it?" he asked.

  "Another ten meters," Murry-Balff replied. "But the Crotonites---

  "Yes. I know."

  From the right, the left, the rear, the three Crotonite land-crawlers came zeroing in, and pulled up in an open are around the two Erthuma vehicles. Wing-Marra, though he knew the gesture was preposterous, let his hand rest lightly on the blaster strapped to the side of his spacesuit. God help us

  all, he told himself, if it comes down to stuff like that. But he felt he

  had at least to make the gesture.

  The Crotonites were out of their land-crawlers, now, six of them, approaching him in the peculiarly dismaying waddling shuffle that they

  employed when they were forced to walk on the surface of a world. Seen

  close up, they were less frightful looking than when flying like devils through the air, because their huge wings were furled and swaddled within their pressure suits. That way, they appeared as short, plump, almost comical little beings, standing no more than waist high to an Erthuma. But they were, Wing-Marra thought, pretty evil looking all the same. The great ungainly bulk of the folded wings behind them provided an ominous reminder of their true forms, and their

  long sharp-featured heads, crested and bony chinned, had a harsh, repellent, monstrous look.

  "Turn on the simultrans," Wing-Marra said to MurryBalff.

  The Crotonites, he knew, would never deign to speak Erthumat. And he knew only seven words in Crotoni, four of them obscene and the others profane. "Who is the leader here?" asked the shortest and fiercestlooking of the Crotonites, one with diabolical yellow eyes streaked with bands of red. Wing-Marra raised his hand. "I am. Captain Hayn WingMarra of the Erthuma research vessel Achilles."

  "I am Hiuptis," said the Crotonite. "What are you doing here, Captain Wing-Marra?"

  "Why, we've been out for a drive. And now we're taking a little walk."

  "I mean what are you doing in this solar system."

  "Carrying out chemical research. We're studying the molecular cloud nearby."

  "And does the molecular cloud extend to the surface of this moon?"

  "Not at all. But while we were in orbit up there we ran into some old friends from Locria, who suggested that we all come down here for a little rest and relaxation."

  "Indeed," said the Crotonite coldly. "This moon is an extremely relaxing place. But I suggest that you enjoy yourselves elsewhere. If you continue in the direction you are traveling, you will very shortly be trespassing on a research center established by and operated for the exclusive use of the Galactic Sphere of Crotonis."

  "Will we?" Wing-Marra said. "A research center, you say? Where? I don't see anything here at all." He took a deep breath and began to move forward, indicating with a small movement of his hand that the others should come with him. "It's absolutely empty out here, so far as I can tell. " Murry-Balff said softly, "You're within two meters of the shield perimeter now, sir."

  "Yes. I know."

  Wing-Marra took another step.

  The Crotomtes began to look extremely agitated. 1"heir bright, beady eyes glearned and flickered, and they shifted their weight awkwardly from one to the other of their short, bhVRe legs. Wing-Marra imagined that they would be flapping their wings, too, if their wings were not pinioned within their pressure suits. As he walked forward, the Crotonites hopped along beside him, keeping pace.

  "One meter, sir," Murry-Balff said.

  Wing-Marra nodded and stepped across the invisible line.

  It was like walking through a wall. Inside, everything was different. He was standing in a kind of antechamber, an open space that curved'off to either side at a wide angle. Behind him was the barren plain, still visible, and straight ahead of him, perhaps fifty meters ahead, lay a zone of absolute blackness, so dense and dark that it could well have been the outer boundary of the universe. The space between the invisible wall to his rear and the blackness ahead formed the antechamber, which was brightly lit by drifting clusters of glowfloats and cluttered everywhere with alien-looking instruments. It was full of Crotonites, too, who were staring at him with a look on their demonic bony faces that was surely the Crotonite equivalent of the most extreme astonishment.

  Murry-Balff, still monitoring everything from the vehicle, said, "There's

  a second shielded zone within the first one, sir. "

  "I'm looking right at it. It's black as the pit."

  "It's totally light absorbent. But the sonar goes through. The city starts

  just on the other side."

  The Crotonite who called itself Hiuptis tapped WingMarra urgently on his thigh. "Now do you see, Captain? Plainly this is a research zone, and delicate observations are in progress."

  "Fascinating," said Wing-Marra. "I never would have believed it. "

  "You concede that we are carrying on research here?"

  "Yes. Yes, of course you are. That's plain to see."

  "Then I call upon you to cease this trespass at once!"

  "Ah, but we're not trespassing, are we?" Wing-Marra

  said lightly. "We're only visiting. It's a purely social thing. This is such a forlorn dead place, this moon. It's good to have the company of one's fellow creatures for a little while in a place like this. And as long as we're here, you really don't mind if we look around a bit, do you? What sort of research did you say you were doing, by the way? I don't seem to recall." Hiuptis turned to the Locrians. " Ship-Commander! " the Crotonite cried sharply. "Will you be a party to this detestable intrusion also? I warn you that you will thereby involve the Galactic Sphere of Locria in the culpability, and our inevitable demand for reparations will extend to your sphere as well as that of Erthuma. You have been warned. "

  "We take note of the warning," said one of the Locrians solemnly. "To which we reply that we are here only because we wish to pay our respects to the representatives of the Galactic Sphere of Crotonis, now that we have become aware that you too are present in this unknown and unclaimed solar system where both we and the Erthumoi have separately been carrying out research programs of our own. I I

  The Locrian's emphasis on unclaimed was subtle but

  "Tell me who you are?"

  "Your friend Vargen was among the newcomers. He co

  "Of course," Vargen replied. "For as long as feasi

  The Locrian's emphasis on unclaimed was subtle but unmistakable. Hiuptis made a sputtering sound. It was shifting from foot to foot again, so quickly that it seemed almost to be hopping.

  Wing-Marra glanced around. The Crotonites within the research station were unarmed, but the six who had come out to intercept the Erthuma vehicles carried blasters. He wondered what the chance was that they would use them if he continued to press forward. Certainly Hiuptis seemed furious, but so far the only threat it had made was that there would be a demand for reparations. Did that mean the Crotonites were ruling out any kind of attempt to end the intrusion by force? Or was Hiuptis merely trying to lull him with some slippery Crotonite sleight of tongue?

  He looked toward Blue Sphere. The Naxian seemed to be aware of what Wing-Marra needed to know. It-she signaled relative calm: The Crotonites were angry, were,

  in fact, fuming mad, but there seemed to be no immediate danger of actual violence.

  Of course, even Naxians weren't infallible. But WingMarra decided to risk it.

  He began to move forward again, toward the strange zone of blackness that lay before him.

  Hiuptis and the other five blaster-equipped Crotonites hopped frantically along at his side. "Captain Wing-Marra! Captain Wing-Marra! Captain Wing-Marra! " Hiuptis cried, again and again, in increasingly excited tones.

  The other Crotonites, those who had been operating the myriad scanning devices that were aimed toward the wall of darkness, were staring at him, frozen with astonishment.

  "Do you mean to go in there?" Hiuptis asked. "Surely not! Surely not, Captain Wing-Marra!"

  Wing-Marra turned toward his Naxian again. Blue Sphere looked troubled now. They are afraid, it-she told Wing-Marra with a silent gesture. They are angry that you are in here where they do not want you to go, but they are afraid, also, of what may happen if you go in there. It is for your sake that they are afraid.

  "MurTy-Balfff' Wing-Marra said. "Do you have any reading on what's going on on the other side of the inner screen? Do you pick up the presence of any Crotonites over there?"

  "I don't, sir, no. But that doesn't mean there aren't any, only that the sonar doesn't-"

  "Right," Wing-Marra said. He looked toward the Locrians. "What about you? Can you try to see through that darkness and tell me what's behind there?" The Locrians, after a moment's hesitation, unveiled their inner eyes, and turned their piercing three-dimensional vision toward the black void ahead. "Buildings," reported one of the Locrians, its voice sounding oddly strangled.

  "Buildings, yes," said the other. "Streets. A whole city is there."

  "No Crotonites?"

  "No living thing at all," the first Locrian said. "It is very quiet in there. It is extremely still. "

  "Fine," Wing-Marra said. "I'll take a look."

  "Captain!" Esiane Ree cried, in horror. "No!"