Charles Sheffield - The Mind Pool

The Pipe-Rilla came last. S’glya had the Angel tucked easily under her midlimbs. She sang softly to herself, until Leah asked her to be quiet. They did not, she reminded all of them, want to attract attention — no matter what was on Travancore to be attracted. The Construct might not be the only danger.

The light slowly faded. At two hundred meters they were moving through a green twilight, floating alone in light gravity as though underwater. A rare upward kink in the tunnel, followed by a more steeply plunging section, took them through a curtain of pulpy leaves. The light level dropped abruptly. The temperature was noticeably higher. By the time they were down three hundred meters they were shrouded in an intense emerald gloom.

Leah stopped and turned to the others. “I can’t see a thing, but I don’t want to use my light. S’glya, you take over the lead. Carry Angel with you. Angel, I want you to use a thermal band and see what you can find out about the path ahead.”

They were still changing places when there was an urgent whistle from Ishmael. “Something ahead! Something moving.”

Leah turned, in time to see a pearly-white glow in the tunnel. As she watched it slid beyond the turn of the spiral wall. A dozen Tinker components disconnected and flew away along the shaft. A minute later they returned, one by one, and rejoined the main body.

“Native form,” said Ishmael after a few seconds. “And large. Over ten meters long, snakelike, no arms or legs. Bioluminescent. The glow comes from a row of lights along each side of it. And it seems afraid of us, because it went wriggling away at a good speed. We followed it as far as a Branch point, about three hundred meters down the shaft.”

“Is it safe to go on?” asked S’glya. They all looked again at Leah.

“I don’t know.” She stared into the gloom ahead, and saw nothing. “If we turn back every time we find evidence of a native life form, we may never get anywhere. So I say we keep going. S’glya, would you lead the way again?’

They continued a cautious descent. Soon they were moving in total darkness. It must be full day above them, but every trace of sunlight from Talitha was blocked by the multiple screens of leaves and stems. At Leah’s request, S’glya shone a faint pencil beam now and again to allow them to see the tunnel for a few paces in front of them. The Angel’s thermal sensor could see far beyond that. It reported that the curving tunnel was clear, as far ahead as fine-of-sight vision could go.

The temperature had stabilized at a level that Leah found just bearable and S’glya relished. The team went on in silence, winding deeper and deeper. The air was denser and more humid, and Leah could smell a faint, pleasant aroma like new-cut Earth flowers. It made her nostalgic for the Gallimaufries and Bozzie’s floral obsession. The tunnel at these depths was less well-maintained, with ragged gaps here and there in its sides and roof. When they came close to one of the bigger holes they heard a soft, rustling sound like wind-blown dry leaves. S’glya reached out to send a more powerful flash of light into the opening. It lit the surroundings as briefly and brightly as lightning. Less than five meters from the tunnel wall Leah saw a small four-legged creature clinging to a thick branch. As the light hit there was a brief quacking sound of alarm.

S’glya pulsed the beam again. The creature turned to face them. Leah had a glimpse of a brown, eyeless head, split by a broad mouth. A second and narrower slit ran all the way across from temple to temple. There was another sound, a high-pitched squeak of fear or complaint, then the animal was scurrying agilely away around the side of the shaft.

“Intelligent?” said Leah.

“According to survey data,” replied Angel, “there are no native intelligent life forms on Travancore.”

“How could a survey know that, without going down to the surface? And none of them did.”

“We were merely reporting what is stated. Ours not to reason why. In any case, intelligence is too subtle an attribute to be inferred from appearance.”

While Angel was speaking, S’glya had switched to a steady illumination and moved the beam slowly around the region just outside the tunnel.

Lean saw the great boles of trees, each one many meters across. The trunks were dark tan and deep purple now, rather than the bright yellow of the upper leaves. From them grew thousands of wilting finger-like excrescences, black and crimson and vivid orange. Legless slug-like creatures on each extrusion inched slowly away from S’glya’s light. As they moved they left faintly glowing trails on the tree fingers.

At this depth, greens and yellows had gone from the vegetation. Photosynthesis was impossible. Everything must depend for its existence on the slow fall of upper-level detritus or the transfer of nutrients up and down the massive trunks. Leah wondered about a pumping system that could lift fluids for five kilometers, even in this weak gravity.

The group went on, always downward. In another hour the pleasant floral scent was replaced by a nauseating stench of fleshy decay. Everything became coated with a misted layer of condensation, and dark, slimy droplets hung from the ribbed roof of the tunnel. Leah felt as though they had been descending for days when finally Angel waved its topmost fronds and poked Ishmael in the side. “We must stop here. Put me down. The tunnel ends in thirty paces.”

Leah came to stand by the Pipe-Rilla. “How does it end?”

“It simply terminates. However, we are less than forty meters above the true surface of Travancore. My microwave sensors tell me that there is solid material beneath us, but descent past this point will be difficult for all except Ishmael’s components. We face a sheer drop, or we must climb down a vertical trunk.”

“Would we be able to move over the surface itself, if once we were there?”

“That should present no difficulty.” Angel paused. “Descent can be made with the aid of a simple rope. But return would present problems, at least for human and Angel forms.”

“I’m not suggesting we go down today.” Leah turned to stare back up the tunnel. Only five kilometers — but five kilometers vertically. “We have a long way to climb, even in this gravity. I propose that we head back and plan a trip with more equipment tomorrow. We know what we need now. The next descent — ” Leah stopped abruptly. Gazing upwards she had seen a movement in the faint scattered fight from S’glya’s pencil beam. It was far above, indistinct, at the very limit of her vision.

“Angel, can you see what that …”

The question became unnecessary. The object was approaching rapidly along the shaft. Its shape was engraved deep in her memory.

Leah was looking at a rounded silver-blue diamond, four meters high and more than two across. At the upper end was a blunt, neckless head with well-defined compound eyes. Latticed wing panels shrouded the middle section of the body. In their folded position they were compact and unobtrusive, no more than pencils of stiff wire. Extended, they could be shaped as needed to form solar panels, communications antennae, or protective shields. The base of the body ended in a tripod of supporting legs, each one able to be totally withdrawn into the body cavity. The mid-section also contained a dozen dark openings. They held the weapons — the lasers, the fusion devices, the shearing cones.

Leah registered everything in a fraction of a second. She gasped and stumbled back a pace along the tunnel. Around her she felt a sudden blizzard of Tinker components as Ishmael dispersed instantly from its composite form. A high-pitched scream of terror came from S’glya.

Angel’s hedging of probabilities back at the tent had been completely appropriate. The Morgan Construct had indeed moved since the time of the orbital survey.