If you submerge yourself in water and have a friend knock a couple of large rocks together repeatedly, starting twenty or thirty yards away and coming closer until you can’t stand it anymore, you may have some idea of what happened.

I can’t describe how it felt. In fact, since it knocked me unconscious for several seconds, it isn’t right to say that I felt anything. There was sensation of a sort, though; perhaps if I were sure just what it feels like to be hit with a sledgehammer simultaneously on every square inch of my body I might use that as an illustration. As it is, I’ll have to let you use your own imagination, aided if you like by the experiment I suggested a moment ago.

The shock affected all of us about equally. It was a minute, perhaps more, before we were swimming as fast as we could back toward the place we had left the others. None of us had any doubt about what had happened; none of us was really eager to go back to the scene.

But we hurried.

I had expected to find four bodies in the mud where our companions had been enjoying their game, but it wasn’t that simple. The wreckage of the sub was about where it had been, as far as I could tell. But the shock wave as the hull imploded had kicked up a cloud of ooze which was still settling, and our lights showed us very little. We stayed close together and swam through the obscurity in all directions, searching every square foot of bottom not only for obvious fragments but for signs of objects buried under recently settled mud. That took no communication to arrange.

We found one of the men partly buried about fifteen feet from the nearest part of the wreck. He seemed intact as far as gross injuries were concerned, but I knew he couldn’t possibly be alive. The shock wave had knocked us out at several hundred yards, and the inverse square law applies under water, too.

We could find none of the others on the bottom, but as the mud settled another of them became visible about twenty feet up, rising very slowly. A thin trail of oily droplets was leaking from the base of his helmet. I hadn’t stopped to think that with the dense liquid filling them, the suits must also have flotation material to let the wearers swim in water. With the heavier liquid leaking out, the fellow’s buoyancy was going positive.

That made it fairly obvious why we couldn’t find the other two. They had probably sprung faster leaks. I could imagine them somewhere above us in the dark, ballooning toward the surface with the last of the liquid that had made their strange lives possible dribbling back toward the sea bottom. I thought of looking for a rain of oily drops which might let us track them, but I had no way of communicating the suggestion to the others, and it was pretty obvious that our lights were far too weak for such a search anyway. The rest of the group had the same general idea, evidently. With the two bodies in tow, we headed back toward the entrance.

I wish there were enough light to read the facial expressions of our companions. I would have liked to be able to guess how they felt about the foreigners whose operations had killed four of their friends. I didn’t know what reason Bert had given for the whole procedure; maybe they thought it was an important piece of engineering research, or something like that. I hoped so. It was bad enough feeling guilty myself, without having the rest of the population down on me too.

I also wished I knew how Bert felt. The victims might have been close friends of his, for all I knew.

I thought I might get some idea when we reached the entrance, but I was disappointed. There was plenty of excitement when we came in, but I simply couldn’t tell what most of the facial expressions meant.

I hadn’t realized how conventional such expressions actually are; unless you’ve grown up in a society where there is a standard face mask for anger, and another for disgust, and so on, reading faces isn’t a very safe way to collect information. The people might have been angry, sad, or disgusted; I couldn’t tell. There was much gesturing among them as the bodies were taken away, and a certain amount between some of them and Bert, but all I can say about their feeling toward us comes from the fact that we weren’t mobbed. I couldn’t even be sure that that situation would last; maybe no close friends or relatives of the victims happened to be present.

Activity around the entrance took half an hour or so to die down to normal. The bodies were finally gone, the men who had been with us had swum off about their own affairs and the swimmers one always seemed to see around any of the entrances were paying no more attention to us than usual. For some of them, that was a good deal; the girl who had gone down to the power section with us was back with her friends.

Bert was finally able to use the writing pad again. There was a lot I would have said — I was still feeling shaken, and guilty, and a lot of other things of which stupid was the kindest — but the same old communication trouble blocked me. There are some times when a man just can’t talk fast enough, and a lot of times when he can’t come even close to writing fast enough.

I rather expected Bert to say something about what had happened, since I was sure enough of his facial expressions to know that he’d been hit pretty hard too. But his writing was confined strictly to business.

“That should convince Marie, if anything will. The best thing will be for you to go to her now, tell her Joey’s sub has been found wrecked and try to persuade her to take her own boat out to see it. Then she may be willing just to keep on going. If she won’t believe you and insists on staying put, we’ll have to bring the wreck in. That’ll have to work. I don’t know what we’ll do if it doesn’t.”

“You could stop feeding her.”

He looked at me and raised one eyebrow.

“Could you?” he scrawled. I shrugged my shoulders, but knew I couldn’t.

“Lead on,” I wrote. He led.

The speechless pauses while I was going from one place to another would have given me all sorts of opportunity to think, and maybe even to see holes in the fabric I’d been so busy weaving, if I were only another hundred percent or so quicker on the uptake. As it was, the next twenty minutes of swimming brought me no ideas at all except details of what to say to Marie.

None of these represented first-class plotting. I was still very uneasy as I swam up to her sub — Bert had stayed out of sight, as before — and tapped on the hull. Fortunately, that attitude fitted perfectly with the act I was supposed to play.

Marie answered almost at once, and her face appeared at the conning port. It was nice to see another set of features on which the expression could be read, even though the expression wasn’t all I would have liked just at first. It softened a little when she recognized me, though. As before, I couldn’t be sure of her vocal intonations, but the words came through understandably enough. ‘Where have you been? I was beginning to think they’d disposed of you, too.” I answered the important part of the remark on the pad.

“Finding things out.”

“From Bert?”

“No. They have a library here, much of it handwritten stuff” by other people who have come down here in the past — and much too much of it for Bert to have written himself. The writings are pretty consistent, and I think I have a fairly sound picture of the whole situation.”

“What did you learn about Joey?”

I hesitated. I had been sure the question would come early, and I had my lie all made up, but telling a lie to Marie came hard. I told myself again that it was in a good cause and started to write, but she had already caught my hesitation, or maybe the expression that went with it — I’ve never claimed to be an actor.