He kept on along the cliff top, toward a point some two miles away where the cliff broke gradually away to the lower level. He was out of direct view from the head of the trail when Swift reached it, but did not let that fact slow him down. Once at the broken-rock region he picked his way carefully down, dodging boulders loosened by a sharp quake, and started back, hiding his little torch as well as he could from anyone overhead. Fifteen minutes after the disturbance had started he was beside Fagin, apparently unnoticed by any of Swift's people.
"Teacher! Do you hear me? It's Nick."
"I hear you, all right. What are you doing here? Did you start this fuss? What's going on, anyway?" "I threw the fire down the cliff, yes; I had to make sure you were here. The rest was a by-product. I'm here because we've found a way to get you out of Swift's hands without having to worry about his getting hold of you again afterward."
"That's encouraging. I thought I had a way, too, but troubles have arisen in that direction. I need badly and quickly all the help I can get, and I can't see Swift being very helpful for some time. Let's hear your idea." Nick described the doings of his people since Fagin had been kidnapped, and dwelt particularly on the geography of the spot where they had spent their first night at the sea.
"We assume," he said, "that you can live under the sea the way you can in rain; so we thought if you fled to this hill, and Swift followed you, he'd be trapped there at night; and while he was asleep you could take away all the weapons of his people - which would be a help anyway, since we're getting so short - and if we couldn't figure out anything else to do with him, just shove him downhill to a point which stays submerged all day." "Would he last long in such a place?"
"Probably not, as there are animals in that sea that ate some of our cattle; but who cares? He didn't mind killing Tom and Alice, and would have done the same to the rest of us if he'd felt it necessary."
"How about the rest of his people?"
"They helped him. I don't care what happens to them."
"Well, I see your point, but I don't entirely share your view. There are reasons which might make you feel differently, but I can't go into them yet.
"Your plan, if it really rates the name yet, has some good points, but it also has some weak ones. If this place of yours is a day and a half's journey from here even for you, I'm not at all clear how I can keep ahead of Swift long enough to let me reach it; remember, you can travel faster than I. Also, now that you've brought them back the fire they'd lost, I'll be very surprised if it's as easy to get away at night as it would have been before." "What do you mean? They brought fire with them from our village."
"They brought it, but didn't know how to make one fire except from another. They let what they had go out during the day after we arrived, and have been fireless ever since. They've been doing their best to teach me their language so I could show them how to make more, but I'm having a lot of trouble - for one thing, I can't make some of their shriller noises. Swift's been remarkably patient, though, I must say. Now he'll be even easier to get along with, I should imagine; but he certainly' won't be easier to get away from." "Then maybe I shouldn't have come, Teacher. I'm sorry."
"I'm not. My original plan for getting in touch with you again has already failed, so if you hadn't come we'd be in even worse shape. All I meant was that we have some heavy planning to do before we're out of this mess. You'd probably better get away for a few hours at least, while I think; there's no point in having you caught by Swift, too."
"But how will I get back again? They have fire, now - for that matter, as soon as they come back they'll know I've been here, and probably start tracking me. I'd probably still be in sight, even if I started now; it's beginning to rain, and I can't travel without a torch, and that will be visible for miles. I was expecting you to come with me right away."
"I see your trouble, but don't quite know what to do about it. It's hard to believe that Swift won't be back here in the next few minutes." Fagin paused, as though in thought; Nick of course did not know that such pauses really meant a tense conference among several men a hundred and sixty thousand miles away. "Look, Nick. There's a good deal of burnable material around, right?"
"Yes."
"And there is only one path from the cliff top, and that a narrow cleft?"
"Yes, not counting the way around - a good four miles."
"Hmph. I could wish it were longer. Do you think you can build a fire big enough to block the foot of that path for a while, so as to delay them while we get going? You'll have to work fast; they must be coming back by now, I should think, unless they're still looking for you on top."
"I'll"try." Nick could see that this was no time for theorizing. "Someone's probably looked over the edge and seen me by now, but there's nothing to lose. If I don't catch up to you, head east-northeast until you reach the sea, then follow along its daytime shoreline until you meet the others. I'll do what I can to interfere with Swift's trackers; you'd better get going now."
Nick didn't wait for a reply; he was already racing toward the foot of the cliff trail, gathering fuel as he went. His torch was nearly gone, but he started a rough heap of wood a few yards inside the cleft, and managed to get it burning. Then he hunted around madly, tossing every bit of combustible matter he could find into the four-yard-wide crack.
A raindrop came squeezing its way down the gully and vanished as it neared the fire, but it was early enough in the evening for there still to be a good deal of oxygen in it. Nick was pleased; evidently no torch-bearing cave dwellers were yet on the path, or the drop would have been destroyed much sooner. That gave so much more time.
With the pile big enough to satisfy him, he set off along Fagin's trail. Even Nick could follow it, a fivefoot-wide track of flattened and crumbled vegetation, except where it led through hollows already filling with liquid water. He could have gone through these with his torch, since the liquid was still fairly safe to breathe, but he chose to detour around. Even so, he caught up with Fagin within a mile.
"Keep going," he said. "I'm going to do a little trail erasing." He applied his torch to a bush beside the trail, and to the crushed, brittle material on the track itself; then he started in a wide arc to the north, setting fire to every bush he passed. Eventually, a glowing belt of radiance extended from Fagin's trail almost east of the cave village around to the track down which the robot had been brought from the north. Nick thought he could hear excited voices from the caves, but wasn't sure. He raced northward at the top of his speed for another mile, and started another series of fires there. They should be visible from the cliff, too; and perhaps the cave dwellers would come out and search along the route to the old village rather than start tracking right away. Then he raced back to intercept Fagin's trail, shielding his torch with his body in the hope that its glow would not be seen from the cliff. He found the trail with little trouble, though Fagin was sensibly keeping to the valleys as much as possible, and finally caught up with the Teacher. Fagin heard his report, and approved. "It's probably the best you could have done," he said. "I'll be surprised if we get through the night without having company, though."
"So will I," admitted Nick.
In spite of this pessimism, the hours passed without any sign of pursuit. Nick's higher speed allowed him to keep up with the robot, even though he had to detour puddles which the machine took in its stride. The raindrops grew clear, and correspondingly dangerous; puddles and lakes larger, deeper, and harder to avoid as the bottom of Tenebra's atmosphere gradually underwent its nightly change in phase.
"Even with your staying on dry land and leaving such an open trail, they must be having trouble following by now," remarked Fagin during one of the brief spells when they were together. "A lot of the places where you went must be well under water by now, and they can't be boiling them off with torches at this hour; the water's too clear to let them get away with it. I'm starting to feel a little happier about the whole situation."
"I'm not," said Nick.
"Why not?"
"The pools are getting very big, and some of the valleys ahead are long and deep. I remember the night before last there were some pretty big rivers emptying into the sea. If we meet one of those, and I don't see how we can help it, we're stuck."
"On the contrary, that seems to me the best thing that could happen. Swift can't follow through a river."
"Neither can I."
"Not under your own power. I can carry you, and it's pretty safe; we haven't met any creatures in sixteen years capable of living, or at least being active, in clear water - though I must admit I've always been expecting it."
"There were some in the ocean."
"That isn't water, for the most part, except late at night. Anyway, I think we needn't worry about ocean life. You've made me happier than I've been for some time; let's look for one of these rivers." "All right. I hope you're right." Nick was accustomed enough to being knocked out by oxygen-free water, but somehow didn't like the idea of being carted around like a sack in that state; If Fagin thought it was all right, though . . .
It looked for a while as though he needn't have worried. With the common perversity of the inanimate, once a river was wanted, none could be found. They kept on their original course, knowing the futility of zigzagging over unknown ground, and got closer and closer to the sea; but they actually reached it, not too many hours before day, without finding a river.
They had reached the "shore" far south of the region where the others awaited them; Nick had selected their course so that there would be no question of which way to turn when they reached the coast. He had mapped enough to know what measuring uncertainties could mean.
Without hesitation, therefore, he directed Fagin to follow the "shore" to the left. They were, of course, far inland from the hill which Nick had planned to use to trap Swift, but that was the least of their troubles at the moment. The chief annoyance was the lack of a river; a second one, which made itself apparent an hour or so after they reached the sea, was the appearance behind them of a distinct glow of light. There was no question what it was; the sun just didn't get that distinct, or even that bright.
"They're gaining on us. I wonder how long my fires delayed them?" muttered Nick when the glow caught his eye. Fagin had not seen it yet, apparently, and Nick saw nothing to be gamed in calling his attention to it. He just looked that much more intensely for a river ahead.
The robot finally spotted the light as well, and understood its meaning as clearly as had Nick. "If they get too close before we find a river, you'd better go on ahead at your best speed; you can probably outrun them."
"What will you do?"
"Go into the ocean."
"Why not take me with you? Won't that be as good as a river?"
"Not according to your own statement. I don't want you eaten right out of my arms, and I'm not very well suited to fighting things off if they attack."
"That's true. I guess your idea is best, then."
As it turned out, though, they didn't have to use it. By the time the glow of Swift's torches had resolved itself into separate points of light, and it could be seen that the cave dwellers were overhauling Fagin and his pupil at a rate that promised a scant hour of further freedom, a bulge had appeared on the landscape ahead; and in another minute or two this had taken on the shape of a low, rounded ridge snaking across the countryside. It had the dark hue of clear water; and well before they reached it there was no doubt that it was a river. Since it reached above Nick's crest, there was no way of telling its width; but it must certainly be wide enough to drown any torches Swift's people might be carrying.
Straight to its edge Fagin and Nick went. Ordinarily such a mass of clear water would be a frightening sight as it oozed slowly by toward the sea; but tonight neither of them felt afraid of it. Nick tossed his torch into it with a carefree gesture, noted with actual glee the way the glow died abruptly from its end, made sure his weapons and fire-drill were securely attached to his harness, and turned to the Teacher. "All right, I'm ready."
The white bulk of the robot slid toward him, and four appendages extended from openings in its smooth carapace. Gripping devices on the ends of these clamped firmly, but not painfully, onto two of Nick's arms and his walking legs, picked him up, and draped him over the machine's back.
"All right, Nick," said Fagin. "Relax. I'll get to high ground as quickly as I can on the other side and dodge raindrops, so you shouldn't be out long. Just relax." Nick obeyed the injunction as well as he could as the machine slid into the river.
His body heat boiled a considerable volume of the liquid into gas as they entered; but the gas was oxygenfree and its physical state made no difference to Nick. He lost consciousness within halfh a minute.
Swift's warriors reached the spot where the trail entered the river fifteen minutes later. The chief was not philosophical enough to put the incident down to experience.
VI. INFORMATION; NAVIGATION; OBSERVATION
"HOW much of a lead will that give you, Doctor?"
Raeker answered without taking his eyes from the robot's screens. "Presumably the rest of the night, and a trifle more - however long it takes that river to dry up after sunrise. It's twenty hours or so to sunrise."
"Maybe the plants will grow enough to hide the robot's trail in that tune; will they?"
"I'm afraid I have no idea."
"After observing the life of this planet for sixteen years? Really, Doctor, I should have supposed you'd know something in that time."
"In all sixteen of those years I never had occasion to note just what kind of vegetation is on the north bank of this river," Raeker retorted a trifle impatiently, "and all I know from Nick about Swift is that he's a good tracker; I have no quantitative information as to just how good. Really, Councillor, I know you have been living in Hell the last three weeks; but if you can give only destructive criticism I can say that you won't be helping her much. You're getting to sound like Aminadabarlee."