"The home sky of the Ancients," he breathed. "From this, we can determine their Sphere of origin...."
He could have stared at the splendor of that strange sky interminably, but tore his eyes away. He looked around the floor of the chamber. It was bare—no machines, no furniture, no bodies. So he still had no clue to the physical aspect of the Ancients. But of course this was only one structure of hundreds. Possibly they had come here to gawk at the vision of the far-distant ancestral home, recharging their spiritual vitality. They must have had eyes, at least. It suggested something fundamentally good about the Ancients; they were, in their fashion, human. They had colonized much of the galaxy, yet they longed for home, and kept its memory fresh. Probably this had been a desolate outpost, a supply station, with forced tours of duty: a necessary function of empire.
Yet it had been wiped out, and suddenly. Perhaps some terrible beam from space had voided their pressure shield, releasing their bubble of atmosphere, killing them all. Maybe an enemy had landed, sacked the post, and removed all artifacts of potential value. In which case there would be nothing left for the archaeologists. Too bad.
"Sol. Spica," the Canopian Master's voice said from Flint's unit, interrupting his musings. "There has been a development. Please return immediately to the collection site."
"What happened?" Flint asked, certain he would not like the reply.
"The representative of Sphere Antares has been killed. I am holding its partner Polaris under guard pending group assembly."
"Oh, no," Flint groaned. "I thought we'd cleared Polaris." He ran for the opening, scrambled out, and landed beside the Spican. "You heard?"
"Dehydrated!" the creature replied in evident horror. To a water entity, dehydration would be a hellish concept on several levels, an obscenity. "Now we know there is a murderer among us."
"But neither you nor me," Flint said. "I was within the dome, with no other exit—and you could not have moved fast enough to do the job, even had you chosen to kill your friend."
"Agreed. We two are innocent—but four suspects remain."
"Polaris, Nath, Mintaka, and Canopus," Flint said. "We must hurry. Would it be permissible for me to carry you?"
"In the circumstance, permissible. But be careful."
"Yes." Flint put his two arms around the glob and heaved it up, feeling the associated Kirlian aura. H:::4 had been right: All entities on this mission were high-Kirlian types. Not just five or ten times normal intensity, but fifty or a hundred. The best their cultures had to offer. High Kirlians for high stakes!
The creature weighed about as much as Flint did, but it shaped itself to the upper contours of his body comfortably and was easy to carry. He ran as fast as he could toward the rendezvous.
The Polarian was there, the Canopian saucer hovering close overhead, as Flint tramped up with his burden. The Mintakan and Nathian had not yet arrived. "What happened?"
"I am under suspicion again," the Polarian said. "My partner of Sphere Antares is defunct."
"I challenged you before," Flint said, setting down the Spican carefully. "But you satisfied me that you were legitimate. I do not believe you would have done it."
"That is most circular of you. But unless you can identify a more immediate suspect—"
"I think we'd better all establish alibis," Flint said. He had a suspect, but didn't care to name it at the moment.
"Alibis?" the Spican inquired.
"Each entity must explain where he was at the time of the murder," Flint explained. "If he were elsewhere, he cannot have been there, so would be innocent."
"Most ingenious," the Spican agreed. "You Solarians do have a marvelous directness. We must also ascertain the mode of demise."
Mintaka and Nath arrived. "This is very bad," the Nathian clicked.
Flint explained about alibis, giving his own and the Spican's.
"Demurral," Mintaka flashed. "We have not verified that there is no other exit to your dome. And if the Spican were the spy, the Antarean would be the first to know it, and would therefore be marked for death. And that death prevents us all from knowing how rapidly that type of entity can move. It could be the fastest among us all."
Devastating logic. Flint and the Spican were back under suspicion.
"However," the Mintakan continued, "the element of velocity is relevant. My companion of Sphere Nath certainly cannot move as rapidly as some of us, and furthermore must leave a typical trail in the dust. Even were I not able to testify that Nath went nowhere without me, the absence of the trail would vindicate him."
"And I assent that the Mintakan was always in my perception," the Nathian said.
"Perception," Flint murmured. "You don't have eyes. How can you be sure—"
"I possess acute auditory and vibratory perception," the Nathian replied a bit tersely. "This is equivalent or superior to your optics. When light fails, you are blind, whereas my sonar—"
"I accept your word," Flint said.
"Nath speaks accurately," the Polarian said. "Their perception of physical objects is excellent. We must accept that alibi."
"You know where that leaves you," Flint said.
"It would be uncircular to misdiagnose any suspect; we must ascertain the truth. We are all suspect, and none of us can alibi the Canopian."
"Correct," H:::4 said. "My craft could readily have traversed the necessary distance and returned, and it is armed. I could certainly have done it, and I am thus a suspect. I suggest, however, that were I the Andromedan agent, I could kill you all now, and could have done so at the outset. I am well armed and have no need to act covertly."
This was exactly what had occurred to Flint. He had avoided a direct accusation because if he proved his point, one pellet or ray from the saucer could wipe him out. But why would the Master bother to kill in secrecy?
Perhaps because he could not safely leave his craft, and had to wait on the explorations of the others. If the secret of the Ancients were discovered here, it had to be salvaged or destroyed, according to the Andromedan view—and salvage would naturally be best. So it was simplest to eliminate any entity who caught on to the spy's identity. Or to keep cutting down the size of the expedition, until the one or two survivors could be controlled.
Flint believed the Polarian was innocent, and doubted that the Spican, handicapped as it was by an unfamiliar body, could have done it. Since the others had alibis, that left Canopus, with all his mobility and armament.
"May I remind you that there remains the possibility of some Ancient agency," H:::4 said. "Perhaps it lacks the power to eliminate all of us, but seeks to sow dissent by selective killings."
There was that. "Let's get together to investigate the crime," Flint said. "Whoever or whatever is stalking us, it seems to strike only isolated entities. If there is safety in numbers, let's take advantage of it." And maybe there'd be a chance to get away from the Canopian craft.
They trekked along the route marked by the Polarian's wheel. The dust was undisturbed here, except for that. No way to conceal the trail. The absence of a trail could only implicate Canopus again.
They approached the mouth of a large runnel angling underground. It seemed to be an avenue for vehicles. That suggested the Ancients did not fly or run rapidly; they preferred to ride.
"We discovered a sealed airlock below," the Polarian explained. "I notified Canopus, who asked me to emerge and show my location so that he could establish it specifically for the other members of the expedition. My companion, Antares, had investigated the lock and informed me that there was operative equipment within. Therefore we felt the discovery was significant."
"When I located Polaris visually, I followed him back to this tunnel, which I could not enter," the Master said. "He entered, then reported the demise of his companion. As you can see, there are no tracks besides those of Polaris and Antares. I therefore placed him under temporary detention and summoned the other members of the expedition."
Flint looked at the tracks. There was no qu
estion: There were three wheel-treads and one pattern of splotches formed by the motion of the Antarean. Polaris had come, gone, and come again, while Antares had come—and stayed. It looked bad for the Polarian: no other tracks, and the Canopian saucer too wide to enter the tunnel.
"It is my turn to remind you that we approached operative Ancient machinery," the Polarian said, applying his ball to his own suit. "That airlock could have opened in my absence...."
"Does anyone on the ground have a power weapon?" Flint inquired. "If that portal should open again—"
There was no response. He knew why: Personal defense was now critical, and a hidden weapon could be more effective than one that was known. "Well," he continued, "be ready to fight or flee, all of you. I'll have my spear, but it has limits."
They entered the tunnel. The Spican began to glow, illuminating it; so did the Polarian. Flint walked first, spear poised, with the Spican close behind; Nath was third, Polaris fourth, and Mintaka brought up the rear.
The passage curved, and terminated at the lock. There was the body. The Antarean's spacesuit had been punctured, just like the suit of Mirzam, and the creature's gelatinous substance had burst out through that round aperture. Explosive decompression, quickly and horribly fatal.
"As you can perceive, I lack the capacity to make a wound of that nature," Polaris said.
"Your ball could vibrate rapidly, abrasively, against a given spot," Spica said. "It would take time to make a hole of that size, but if Antares were unconscious—"
"My spear might make a similar hole," Flint pointed out. "Or a laser beam. Or a conglomeration of sharp little hooks."
"Could Canopus have dismounted from his craft?" Spica asked. "While Polaris was absent?"
"Yes," Flint said. "And Canopus may be able to fly on his own. He is of insectoid derivation, with wings—"
"Not in vacuum," Mintaka pointed out. That popped that bubble. Mintaka had a way of doing that; very sharp mind. Wings needed atmosphere in order to function.
"But a jet pack?" Flint inquired.
"Then we all remain suspect," Nath said. "Any one of us could have hidden a flying device."
"Not so," Polaris said. "Such devices create turbulence, especially in confined spaces, and the prints are undisturbed."
"It becomes difficult to separate circularity from suicide," Nath remarked, since the Polarian seemed to have brought suspicion on himself again. "But I believe I can exonerate Polaris. I noted three wheel-tracks. Do your perceptions concur?"
"Yes," Flint said. "What's your point?"
"There should be four."
"That is correct," Polaris said. "I arrived with my companion, left to notify Canopus of the route, re-entered to discover the murder, and reemerged. Four tracks."
"Prior to our present entry," Flint agreed. "You must have used one track twice."
"I did not. The taste of one's own trail quickly palls. That is a maxim among my kind, with philosophic undertones but nevertheless also literally true. My wheel is encased in its own suit, but it is not my habit to repeat a specific route exactly. I made four trails."
"Yet there are only three," Nath clicked. "Therefore one must have been erased."
"How could that happen in this dust?" Flint asked. "And why would anyone bother?"
"Perhaps it was the killer's own trail being erased, and the Polarian's trail was coincidental. Sonic application could do this."
Flint's eyes narrowed. "Could you do it?"
"Yes." And Nath demonstrated by clicking his hooks together in such a way as to cause the nearby dust to jump and resettle around it, wiping out its own trail.
"But Nath did not," Mintaka said. "He remained with me—and there are no gaps in his own trail."
"More than can be said for mine," Spica said. "My partner carried me partway."
"We now have a possible method," Flint said. "But it doesn't help much. Any of us, including Canopus, might have done it; it is evident that we hardly know enough about each other's capacities to be assured otherwise."
"Were I the guilty party," H:::4 said in their translators, "I could bomb the entrance to the tunnel and destroy you all. I admit the capability; I deny guilt or intent. Judge me unfairly, and you only strengthen the position of the actual spy."
"Maybe we'd better agree that there is an Ancient robot stalking us," Flint said, glancing nervously at the tunnel entrance. He had thought they would be safe from Canopus here, but obviously they weren't. There was no way out but forward—through the Ancient airlock. "It killed Mirzam, but could not catch the rest of us alone, until it found Antares. It is now outside, having erased its trail, waiting for us to separate again."
"This seems to be a satisfactory hypothesis," Mintaka flashed. "But it does not alleviate our peril. If it has laser armament, even Canopus is not safe."
"Why wait for it to strike again?" Flint asked. "Let's force open this lock and plumb its secrets. We have nothing to lose."
"Pull-hook."
"Concurrence," Mintaka said.
"Agreement," Spica finished.
"I, too, am amenable," H:::4 said. "I shall remain on guard. My apologies to Polaris; my suspicion was premature."
"Circularity."
Flint examined the lock. "This is a simple gear-and-pinion system," he said, glad of the dull training he had been given on Earth. "The Ancients must have had hands like mine." Could the Ancients have been humanoid? No, that was too much to expect of coincidence. He took hold of a half-wheel and turned.
To his surprise, it moved. Something clicked; then a blast of air shot out through a vent, almost knocking him over despite the baffle that inhibited its force. "Depressurization," he said. "For three million years it held its air—that's some mechanism." Truly a Titan, he added mentally.
"Evidence that the Ancients can retain operative mechanisms today," Mintaka said. "We are surely very close to significance."
Now the lock swung open to reveal a fair-sized inner chamber. "Canopus, we are entering the inner sanctum," Flint announced. "If our communications cut off, you had better return to your Sphere and issue a report." And if you are our spy, we are safe from you, he thought. And you won't get the secret of the Ancients. That's why none of us can afford to go home: We might miss the crucial discovery of the millennium.
"Understood. I will maintain contact if this is feasible. Under no circumstance will I dismount from my craft."
"Right." They crowded into the lock, and Flint pulled the door closed.
Immediately the locking mechanism clicked it tight. Air hissed in, pressurizing the chamber. "But let's keep our suits on," Flint said.
"It is helium gas, almost pure," Nath said. "Inert, but not suitable for normal life processes."
"I thought as much," Flint said. "Normal atmosphere on any world has corrosive properties."
"Sentience is corrosive," Mintaka remarked.
When pressure was up to about twenty pounds per square inch, making Flint feel as if he were in water, the hissing stopped. He worked the half-wheel on the inner door, and it opened.
It was a large chamber, illuminated by a gentle glow from the walls, with several passages radiating out from it. In the center was a circular platform enclosed by a pattern of wire mesh. There seemed to be an elevator or hoist within it, the cage suspended about twice Flint's height above the floor. That was all.
"Empty," Flint said, disappointed. "They must have cleaned it out before they closed up shop, after the wipe-out. Took all the bodies and equipment."
"Yet machinery below and around us is functional," Spica said.
"Oh? Where are the machines?" Flint asked. "I mean, specifically."
"Below me, here. Operative but not mechanical," Nath replied.
"Electrical in nature," Spica said. "I regret I am unable to utilize the full propensities of this body. The native Antarean could have read the flux precisely."
"You can perceive magnetic flow?" Nath asked.
"Yes. And the finer manifestatio
ns such as the Kirlian aura. Not merely as a presence, but as a specific pattern, typical of any given entity. This is a good body."
Something fell into place in Flint's mind. Sphere Antares had possessed the secret of natural transfer for centuries, so would be long familiar with related nuances. "Can you distinguish between a native entity and a transferee?"
"This is simple for Antares. Difficult for me, since—"
Flint kept his body relaxed, his voice casual, but he was ready to explode into action. "Are any of us transferees?"
"No. Only myself. My friend Antares verified this at the outset, and intended to inform you, being concerned that—"
"Including Canopus?"
"Canopus is native. This is assured."
So there were no transfer traitors among them after all. They were all the creatures they appeared to be. Had the Spican been the spy, it would have accused one of the others instead of exonerating them.
"Caution," Mintaka flashed. "Antares was within range of operative Ancient circuitry, detecting its function and pattern. The Ancient equipment should similarly be able to detect capacities in us. Antares was quickly killed. You, Spica, may now be in similar danger."
"We're all in danger," Flint said. "But I agree we'd better keep close watch on Spica."
"Triple appreciation," the Spican said. "I shall try to analyze this alien field further. I do not think it is capable of physical action, however."
Such as puncturing a spacesuit? That was certainly no magnetic phenomenon. Unless: "Electric engines are magnetic, and we have magnetic pistols in Sphere Sol. Could an Ancient circuit have—?"
"That was one of my considerations," Spica said. "As I orient on the fields of this site, I verify: The operative element is not capable of physical action. The currents are very fine, akin to those of living nervous circuits. No motors or heating units."
"Surely the Titan wasn't a pacifist!" Flint murmured dubiously. But he remembered those fascinating stars, obviously esthetic rather than practical, there in the dome. Had the Ancients' culture been as far beyond the contemporary scene as their technology?