And then there were dangerous life-forms. To be dangerous, life did not have to be smart. It merely had to be hungry, poisonous, bad-tempered, territorial, frightened, or accidentally lethal. Bony, as an Earth form, was almost certainly useless as food for any indigenous form on Limbo or any other alien planet. Unfortunately, that was the sort of discovery a creature made only after an attempt at eating had begun.
Occupied by such disturbing thoughts, Bony came to the top of the ridge. He guessed that he had walked maybe two or three hundred meters and risen twenty meters above the ship’s location at the bottom of the valley. Everything was noticeably brighter. He raised his head and stared straight up, wondering how far he was from the surface. When they first arrived, he had guessed at maybe a sixty-meter depth for the Mood Indigo based upon the pressure outside the ship. But that estimate, he now realized, had ignored the air pressure of the atmosphere above the surface of the water. He might be within ten or fifteen meters of air — whatever air on Limbo might be. It must have a high oxygen content, because the waters of Limbo literally fizzed with dissolved oxygen.
The far side of the ridge descended in a shallower slope that seemed to lead to another valley. The seabed structures changed again. Now they formed clumps of long green strands with thick purple fingers at the end of each. Bony decided that he had come far enough for one day. He would, if the ship was still here tomorrow, take a closer look then. He was all ready to turn and head back when he noticed something about the green clumps. Although their height and degree of growth varied so that they covered almost the whole seabed apparently at random, the positions of their centers were not at all haphazard. They lay along a precise triangular grid, each one about half a meter from its three nearest neighbors.
It could happen naturally. For all that Bony knew, the separation was governed by some precise biological demand for light or nutrients. If, on the other hand, it was not natural, but a farm …
Bony sank down on his haunches to examine the nearest clump of plants. He reached out and tugged at one of the purple fingers. It came away easily and split open like a ripe pod, revealing a group of pea-sized objects within. A puff of gas came at the same time, bubbling up into the water. He lifted the pod to the visor of his suit helmet for a closer view of the dimpled seeds. They looked like a food crop, ripely edible — though probably not to humans. One of those might be enough to kill Bony. As he peered at the cluster his peripheral vision caught a movement far away.
They were on the floor of the valley, close to the limit of visibility. Three of them. At that distance, in the diffuse watery gloom, he had no way of judging size. Each one was rounded and iridescent, like an object blown from a collection of different-sized soap bubbles or a figure made by children from balloons, come to life and in its movements oddly ominous. Bony saw — or imagined — a round bubble head supporting bubble eyes that nodded on long thin stalks; a spherical multicolored body; string-of-bubble limbs or tentacles, that carried the creatures across the seabed as though they were floating ghosts.
Carried them this way . By accident, or by intention? Bony did not care to find out which. He had enjoyed as much novelty as he could stand, and his stomach felt knotted with tension. He stooped, to provide as small a visible target as possible, turned, and started back toward the Mood Indigo. He told himself that there were multiple good reasons for going back. Liddy would be worrying about him. He wanted to see her. He was hungry and thirsty. His bladder was uncomfortably full, and although the suit would accommodate such things he preferred the ship’s facilities. Even the uncertain pleasures of Friday Indigo’s company seemed desirable, compared with that of the creatures — Limbo-ers? Limbics? — slithering toward him across the alien corn of the underwater valley.
Only one thing preserved the dignity of Bony’s retreat: it was physically impossible to run underwater.
As soon as the ship came into sight he turned to look back. He was glad to find that he left no telltale track of suspended seabed mud, nor could he see any sign of the bubble creatures.
Even so, the relief when he reached the protective bulk of the Mood Indigo and stood once more below the open airlock was considerable. He didn’t feel hungry any more, and the urge to pee had mysteriously vanished. He crouched, leaped, and was able to grab the edge of the hatch on the first try. His head came above the surface of the water, and with another upward heave he was sprawled on the bottom of the lock. He stood up and splashed through knee-deep water to the port on the inner hatch. As he had hoped, Liddy was there. He gave her a thumbs-up and started the process of pumping air that would clear the lock of water. The air pressure in the lock was only thirty percent higher than inside the ship, and the water level dropped as he watched.
He removed his helmet as the outer hatch closed. By the time that Liddy matched air pressures and opened the inner hatch he had his suit halfway off. She interfered with that by coming up behind and giving him a hug.
“I wondered where you’d gone. You disappeared completely.”
“I thought that since I was outside and the suit worked fine, I’d take a little look around.” Bony tried to be casual. “Where is Friday Indigo?”
“Sleeping, I guess. I haven’t heard a sound from up there.”
“Still? But he’s been asleep for—” Bony saw the clock. “That can’t be right. I was gone for hours.”
“Thirty-seven minutes, from the time you dropped out of the hatch to the time I saw you coming back. What did you find?”
“Lots of things.”
Before Bony could say more, a voice from overhead grumbled, “You sure make a hell of a lot of noise down there. Have we sprung a leak or something? I heard a pump.”
Friday Indigo came down the ladder. His dark hair was a tousled mess, but he seemed in a surprisingly good mood.
“An air pump,” Bony said. “I’ve been outside, and when I came back in I had to pump water out of the lock. Captain, I think we ought to try to make drive modifications, raise the ship off the bottom, and get out of here as soon as possible.”
“What’s the hurry all of a sudden?” Indigo wandered into the galley and came out carrying a can of juice. He gulped from it noisily. “We have air, we have food, and the ship isn’t about to cave in. I didn’t come all this way so we could turn right around and leave.”
Bony wondered if it was bravery or stupidity. Did Indigo have any idea of their situation? “I see several reasons to leave, sir. First, we have no idea where we are. As I understand the Link Network, it is impossible to make a Link to a place where matter is present. Even a Link into air requires special procedures. But we arrived in water .”
“All that proves is that you don’t understand the Link Network. Nor do I, and nor I suspect does anyone else. But I’m not in a sweat because of it. What else?”
“We’ve landed in a place like none I’ve ever heard of. The sea here isn’t ordinary water, it’s deuterium oxide — heavy water.”
Friday Indigo said to Liddy, “Remember I told him it was water?” And then to Bony, “So it’s heavy water. I’ve heard of that. How dangerous is it?”
“Not dangerous at all. I think. But it’s — well, unnatural for an ocean to be heavy water. In Earth’s oceans, heavy water is only one part in six thousand.”
“Precisely why we came. For strangeness.” Indigo tossed the empty can into a trash-squeeze and rubbed his hands together. “This is terrific. We’ve found a whole new world, one nobody has explored before. That information alone is enough to make this expedition famous. And when we get some idea of what sort of things might be here …”