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 manifestations 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.”