"Right," he answered. "They found the generator shield, apparently read its lettering carefully, which the Hunter says would have let them identify his quarry's ship, and for some reason neither of us has been able to guess so far they moved the shield from Apu into the lagoon a mile or so, where Maeta found it. This happened several years ago, but the Hunter is certain, they wouldn't have left Earth, at least not for good. They may, he admits, have spread out from the island either to look for him and his quarry because they couldn't find them here, or to check up on the people of Earth, or both. . He is certain they would come back from time to time to check on the ship which they probably found, or both of them which they may have found. All we have to do is find at least one of them ourselves and leave a message with it."

"Two questions," Seever spoke slowly, choosing his words carefully. "First, why would they have moved the shield? It seems to me you're pa.s.sing over that question very casually, and you admit you haven't an answer. Second, why do you have to find the ships, or one of them, to leave a message? I could see it as a problem when your friends might have been anywhere on Earth, but you now seem sure they're on Ell at least some of the time, why not paint a message un-obtrusively under the dock?"

Bob sighed. "The second answer is the same as it always was.

We still have to avoid attracting human attention. A message with any usable detail will be regular and complex enough to get not just attention but real curiosity. Both the Hunter and I feel we can't afford that. For the other point, granted it may be important but we don't see how it can affect our plans. We'd love to figure out the answer, or have someone ' else come up with a convincing one.

Until someone does, we'll have to wonder."

The doctor was silent for at least a minute. "I still don't like it,"

he said last. "I was hoping the Hunter might recognize it as some sort of standard procedure with his police. Maybe it's not important, but I don't like jigsaw puzzles with big gaps in them, especially when there are no pieces lying around. However, we'll have to live with the situation, I guess. You really can't think of a reason, Hunter?"

"I can think of several," the alien relayed through Bob. "It isn't just a matter of police procedure, which is not itself just a matter of following rules. There are dozens or hundreds of situations in which moving the shield would be the obvious thing to do. I was going to do it myself if we had found it on Apu, in an attempt to backtrack to the other ship. Clearly, whoever did it this time was not backtracking.''

"Why not?" asked Jenny. "Do you really know the other ship didn't land in the lagoon?"

"Of course not," the alien replied, but backtracking on the comparatively open and smooth lagoon floor would be pointless; from what I've seen, one could go anywhere with equal ease. I was hoping, though not very strongly, that there would be only a few lines of possible travel outside the reef. Anyway, Doctor, I have little doubt that when we do find out why the thing was moved we'll agree it was a good, sound reason, but I don't think I'll be embarra.s.sed for not guessing beforehand what it was. There are just too many good possibilities."

Seever nodded acceptance of the point, and went on talking.

"All right. That leaves us with straight procedure-, problems.

We've made the diagnosis; we have to plan the operation. It seems to consist of hanging this, gadget over the side of a boat in all the reasonable places we can think of. These unfortunately include the ocean to the west of the reef, which means we have to keep the machine from getting tangled in bottom coral, and also keep the boat off the reef itself. If you think the crash may have occurred within the reef, I'm completely stumped on what you can do. Bluntly, I very much dislike the idea of taking Jenny's boat outside to windward, and the west side is windward most of the time. You'll have to be careful. I won't forbid it, but I hope you'll use common sense.

"Personally, I'd strongly advise getting a better boat-no reflection on yours, Daughter, but I'd be much happier if you had power available. Since I think it would be silly to trail the detector overside blindly, you should wait for the diving gear that Arthur has ordered; and I'd spend the interval finding a powered craft and arranging to borrow it. You'll also have to try tying your work schedule with those of the people helping you; remember, you won't have as much free time as you like. You do start work shortly, I a.s.sume?"

"I'd almost forgotten," Bob admitted. "You haven't come up with any excuse, I take it."

"None that would hold up if you're going to be seen, diving several hours a day. Of course, you could take Old Toke into the secret and have him put you to work looking for s.p.a.ceships."

"We've been through all that. No, thanks."

"Well, we've been through this too, but here it comes again. I think we're going to need more people to get the job done. Your father and I won't be able to help much, on simple time criteria.

Your mother may be free a little more of the day, but she has Daphne to take care of at unpredictable times. I can let Jenny off, of course, to suit the needs of the situation, but neither she nor anyone else should be out there alone."

"She wouldn't be alone. I'll be there."

"And if one of your interesting medical problems rears its head-especially if you're under water?"

"Well-" Bob fell silent.

"Remember, if I do the recruiting no one will doubt your sanity.

I'm willing to let them doubt mine." "You shouldn't be. You're the only doctor on Ell, if they lose confidence in you, you won't be here long."

"I can prove what I say."

"So could I," retorted Bob, "if anyone would pay attention. The trouble is talking to someone who's walking off shaking his head."

"Have you ever had that happen?"

"No. I'm going by what I'd do myself. Be honest Doc. When I first told you about the Hunter, what would you have done if you hadn't considered it your medical duty to humor me?" It was Seever's turn to be silent.

"All right," he said at last. "But there are people who would normally humor me."

"Your wife, of course," admitted Bob. "But who else?"

"She'll do to start with. In addition, I'd take a chance on the Teroa girl you've already set wondering about you. She's known to be extremely competent in the water. I'll bet she could cover a good deal of the area you want to search, even before the diving equipment arrives."

The Hunter had already considered this point and added his voice to the argument, but Bob was still under the pressure of over seven years' conditioning, He had not been able to bring himself to veto Seever's request to tell his wife, and had even managed to tell Jenny himself, for reasons which were still not clear to him; but that was as far as he wanted to go for the moment. He didn't phrase it just that way, but both the doctor and the symbiont could see the situation. They gave up for the time being, and the group went back to the logistics problem of planning a way which would give Bob a full day's work without his troubles' being spotted. This seemed to be Seever's business.

"I still haven't found an argument which will get you entirely off work and yet let you go diving, except the one you reject,' the doctor said slowly. "I may, though, be able to come up with something which will keep you away from heavy muscle work.

"There were enough peculiar results in your blood tests to write a good monograph. There is something odd about your calcium. The Hunter isn't doing a perfect job with your sugar. I don't think you'd clot even a pinp.r.i.c.k without him, and you don't seem to have any adrenaline at all. He must be doing something or supplying something that does an equivalent job or you'd be pretty dead, but it isn't adrenaline. I can honestly report that your tests are peculiar, but. . ."

Seever let his voice trail off.

"But PFI might react by sending me to Tahiti, or even to j.a.pan or the States, for more checkups and treatment." "Can't you tell them just a little? That the tests seem funny and you want to make sure, and I should be kept at desk work or something so you can get at me whenever you want during the day? If I'm not doing heavy work I might either avoid the fatigue or be able to hide it, and I can cover up the joint pains well enough."

"That's all I can see our doing for now," Seever agreed. "I'll write it up that way, and you report for work tomorrow and see what happens. We may as well try it this way. I don't see what else we can work on until the diving gear comes, since you won't let Maeta in on the operation."

"I'm not quite sure about that." Jenny spoke up for the first time since the medical questions had come up. Both men looked at her inquiringly, and her father asked for clarification.

"You mean we can do something to get the equipment here sooner? Or do you know of some here already?"

"Neither. I think I have an idea about getting something done before the diving stuff arrives at all. I'm not really sure, and I want to think it over. Bob, if you'll come here tomorrow after work-you'll want to anyway, so Dad can see how you're doing-I think maybe I can come up with something that will bypa.s.s the diving equipment for a while. All right?"

"You're sure you don't want to tell us now?" asked Bob. "It could save a day, you know."

"I'm sure I don't, because I'm not sure I'm right I don't want to look silly." Bob looked at her father, who shrugged.

"I guess that adjourns the meeting," he said. "Bob, you go home and get as many hours sleep as you possibly can. Hunter, there's nothing I can tell you to do. Jenny, work your think box, and if I can help any way without b.u.t.ting into your secret, tell me. One other thing, Bob; drop by on your way to work in the morning and pick up my report on you. I'll do my best, but don't expect too much. Old Toke has always had the idea that recent graduates should be impressed as quickly as possible with the fact that they're not really indispensable, or even very important."

The meeting broke up. Bob went home without any attempt to adjust his bicycle, and he was late getting the rest Seever had recommended because Daphne was on hand.

After she went to bed he updated his parents on progress, but omitted any mention of the bicycle incident. The Hunter spent the night on biochemical work which might or might not have been useful; Bob did not have the joint pains in the morning. Seever's re-port apparently accomplished something, for the Hunter and his host spent the day in the refinery watching dials and turning valves. The work wasn't too hard. Bob's muscles held out to get him back to the doctor's in the late afternoon.

And Jenny's idea was of the sort one kicks one's self for not thinking of earlier.

8. Routine, Modified

It may not have been completely safe, but for the Hunter it was quite comfortable. A foot-and-a-half length of three-inch pipe had been secured with wire to one side of the concrete outer case of the metal-detector. A wooden plug closed the upper end of the pipe. The inner side of the plug held a small improvised electric switch, which closed the circuit in a two-strand wire leading up along the rope which supported everything. The Hunter could send buzzer signals to those above, though they had no direct communication with him so far.

The bottom of the pipe was open, allowing the alien to look down with an eye composed of his own tissue. It was planned to make an artificial one for him from a lens and a short cylinder of opaque material, but this had not yet been completed. It would have advantages; the Hunter's flesh was not completely transparent, so that it did not make a particularly, and was not completely opaque so that his "eye" did not exclude stray light really well. He could see, but generally preferred other eyes to his own.

The bottom was very irregular, and the coral growing from it was even more so, so he had to keep sending "up" and "down"

signals to the people above. The most inconvenient part of the setup was the fact that the phones of the detector were also up in the boat, and there was no convenient way for Bob and Jenny to let the Hunter know when the device responded. They had tried tying a string to a washer held in the Hunter's tissue inside the pipe, but there were so many spurious signals from the boat's own motion that this had been given up. Bob had suggested a flashlight bulb in the pipe, operated by a key in the boat through a separate circuit, but this had not yet been built.

Over a week had pa.s.sed since Jenny's suggestion had been made. Between work and weather, very few hours had been spent in actual search. The vague beginnings of a map of the sea's bottom beyond the reef existed, but filled a very small fraction of the master sheet which Arthur Kinnaird had made, from the company map of the reef itself.

Checking the position of the boat every minute or two in order to keep track of the area which had been covered was a major nuisance, even though a brain-storming session in which all had partic.i.p.ated one evening had resulted in a fairly rapid fix technique based on horizontal angles measured between corners of selected pairs of the tanks in the lagoon. The Hunter would buzz a number whenever he saw a fairly distinctive feature, and note its details with a piece of pencil graphite on a sheet of paper lining the pipe; at the sound of the buzz, those in the boat would measure and record position. During the evenings of days when they managed to work at all, the Hunter and Bob would correlate the sets of records, and make the appropriate additions to the main chart.

There was a good deal of metal on the bottom; human beings seemed to have a tendency to lose things overboard. So far, all the specimens had been too small to give signals which could possibly be from a s.p.a.ceship, except for one which had been found the first hour of operation. Checking it out had been long and complicated; the word had not reached the Hunter until the kayak had pulled into North Beach for rest and lunch. Afterward the site had to be found again, and the Hunter lowered to the bottom so that he could extend a pseudopod into the mud to a.n.a.lyze the object. It had proved to be a well-rusted, extremely large anchor. All the Hunter could do was buzz "no" to his crew.

When he gave them the details later, they guessed it had been lost from a sailing ship at least a century before, possibly while trying to hold off the reef during a storm.

Procedures were gradually improved as the days went on, but the charted area increased with painful slowness. There was no real danger, though the Hunter was constantly beset by very small fish and arthropods. Biochemically his tissues were Earthlike enough to be digestible by Earth organisms, and conversely; it was something of a race every hour he was in the water to see who ate more of whom. Because of the protection of the pipe, the Hunter was able to keep ahead, but he realized how lucky he had been to meet and occupy the shark so soon after his crash beside the island.

For Bob, the days were not going very badly; fate seemed to be holding its fire for the moment. He had not suffered the strange fatigue for nearly two weeks, either because of or in spite of Seever's and the Hunter's combined efforts there was no way to tell. To forestall any complacency, the weariness had been re- placed by the joint pains in more serious form, and, after a few days, by muscle aches and cramps. The cramps were usually in the legs and waist, and some-times he was finding it difficult to conceal them from his fellow workers; they struck suddenly and without warning. Malmstrom, whom he saw at times, made occasional remarks about his old friend's deteriorated condition but didn't seem to mean them too seriously so far.

The PFI work had been a nuisance mostly because of the time it demanded. Bob liked it well enough for it's own sake, and even the Hunter was interested. Jenny had suggested that she take the Hunter out during Bob's work hours, accompanied either by her own father or Bob's, but the Hunter had firmly vetoed this. It was bad enough, from the alien's viewpoint, to leave his host for a few hours at a time even when they remained near each other and could rejoin on a few minutes notice. If they were apart by the three or four miles which separated the search area from the refinery, he would not even know if he was needed for perhaps hours.

About the fifth day of actual search-as Seever had predicted, wind permitted their operation much less than half the time, and they had met with no success in borrowing a powered craft-a problem which no one had seriously considered developed, to show that any separation at all of host and symbiont could lead to trouble.

It was about half an hour before sunset. The Hunter had been rather pitying the boring time his young friends must be having, in contrast to his own, when the situation changed abruptly.

The Hunter was several seconds realizing what had happened.

The motions of the boat were always providing some vertical acceleration, and no shock or blow accompanied the parting of the rope. It just quietly let go, and the detector and the Hunter were on their way to the bottom. There was a slight jolt as the wire took the load. This, surprisingly, held, jerking the wooden plug out of the top of the pipe and taking the switch and almost taking some of the alien's tissue with it. By the time he had recovered from this surprise, he and the detector were half buried in slimy mud.

Three and a half fathoms above, consternation reigned. Bob had been holding the rope while Jenny held position with the paddle, but she knew almost as soon as he did what had happened. Small as the loss was, its disappearance had altered the trim of the kayak, and the girl knew her craft very well indeed.

"Did you drop him? Have your muscles quit again?" she asked anxiously.

"No. The rope seems to have broken or come un-tied. If I'd lost my hold we'd still have him; I had it snubbed on a cleat."

"Take the paddle, and hold us here!" the girl snapped. He turned to see that she was already strip-ping down to her bathing suit.

"No! Wait!" he said. "Make sure we know what the position is, first!" He s.n.a.t.c.hed the s.e.xtant, made quick readings on the reference tanks, and wrote them down. Then he started to remove his own shirt, remarking as he did so, "We ought to have had some sort of emergency buoy that we could throw over to mark the spot when something like this happens."

"What are you doing? You can't go down!" snapped Jenny.

"You're not even as good a swimmer as I am when you're in good health, let alone now."

"And I'm not as good a paddler, and if you do go down and find the other end of the rope somewhere on the bottom, what are the chances of my keeping the upper end in your reach?"

"Do your best. Give me the free end, pay out all the slack you have, and take the paddle." Bob followed instructions, not because he was convinced she was right, but because it seemed a poor time to argue, and Jenny disappeared overboard.

The Hunter could see the canoe, and saw the girl enter the water. Neither view was very encouraging. The kayak had already drifted at least twenty yards from his position, and Jenny, while apparently going as nearly straight down as she could, seemed unlikely to get anywhere near him. Indeed, she did not even reach the bottom; with a fathom still to go, her descent slowed and stopped. She drifted for a moment, evidently trying to see, but her natural buoyancy took over, and after a few seconds she began a.s.sisting it.

Her head broke the surface a dozen feet from the kayak. Bob, forgetting for the moment the importance of trying to hold position, paddled over to her while she was getting her breath.

"Any luck?" he asked. She climbed back aboard before answering.

"No. I couldn't quite get to the bottom. We should have goggles; I couldn't see clearly enough to spot the -box and pipe, to say nothing of the rope. The sun will be down soon, too. There isn't a chance of finding him tonight. We'll go in, and you get in touch with people and arrange enough time-swapping at the refinery so you can spend all day tomorrow out here."

"I don't like to leave-"

"I don't either, but it's a case of what we can do, not what we want to do."

"But the Hunter could leave the pipe and swim to the boat, if we wait long enough."

"Fighting off all the small fish and animals he's been telling about? He's too smart to try, I'd think. Could he find us in the dark?"

"I don't suppose so. His eyes aren't too good." "Well, we'll compromise. We'll stay as close to the spot as we can until sunset.

If he hasn't shown up by that time-and I still don't think he's dumb enough to try because he'll know we can find the instrument more easily than anything else-we'll go in, and you'll do what I told you."

"All right. What will you do?"

"Go home and report to Dad, make a couple of marker buoys as you were suggesting, and think."

She did not mention that she had already been thinking, and fully intended to do something else.

The Hunter watched the boat hopefully until the light failed, rather wondering why no one dived again and what was going on up above. Jenny was quite right on one point; he did not consider for a moment leaving the shelter of the pipe and trying to swim to the kayak. He waited. When the light faded and he could no longer see the surface, the boat, or anything else but a few luminous life forms, he continued to wait. There seemed nothing else to do but think, and he had to do that anyway.

Jenny and Bob left the kayak at North Beach, the point at the end of Ell's longer arm, where the Hunter had come ash.o.r.e and found Bob nearly eight years before. Their bicycles were there, since they had been using this as a staging area from the beginning in order to save time, but there was no moon and no easy way of keeping the machines on the road, so they were some time getting even as far as Bob's house. He stayed there very briefly, telling his mother that they were off the water but that he had to get to a telephone, and went on to fulfill the a.s.signment which Jenny had given him.

The girl herself had not stopped. She went on to the Teroa home and asked to see Maeta. The latter turned out to be at the library. Jenny went there, found the other girl downstairs working on new books-Bob's were not the only cratefuls to reach Ell each June-asked her to come outside where they would not be overheard, and told her the whole story.

Maeta had of course been wondering about the things Bob had said in his unguarded moment, but this did not make Jenny's tale any easier to believe.

Jenny was both insistent and persuasive, however, and the older girl eventually agreed to go to the Seever house.

There, the report of the Hunter's loss produced such obviously genuine concern on the part of the doctor, and his wife that Maeta's skepticism weakened. Seever added verbal a.s.surance of the truth of the whole story, with details from the old detective adventure which Jenny had not known. Finally, still with some reservations, Maeta agreed to offer her aquatic skill to help in the recovery of the equipment and, if he existed, of the Hunter. She also agreed to furnish her own outrigger a more stable and capacious craft than the kayak. Since she was not on duty at the library the next day, there would not be the problem of sending a subst.i.tute.

When Maeta had left, Seever looked quizzically at his daughter, and asked, "What excuse are you going to make to Bob for this piece of recruiting?"

"If he thinks excuses are needed, his brain really is getting soft.

If he doesn't like it, he can just stew. Are you suggesting that you don't like it, either?"

"On the contrary," her father a.s.sured her. "It was the smartest thing you could have done. I'm not sure I'd have had the-er- force of personality needed to do it, that's all. Bob is not entirely out of order, feeling the way he does."

Jenny refused to pursue the subject.

"Do we have any good, strong twine here, or will I have to go to the store in the morning?" she asked. "I've got to make some marker buoys."