It took me perhaps twenty minutes to walk down, fill the three bottles, and walk back, so when I returned to the AT it had been about forty minutes since I had seen Katz. Even if he had tarried on the mountaintop, and even allowing for his modest walking speed, he should have reached here by now. Besides, it was an easy walk and I knew he was thirsty, so it was odd that he wasn’t more prompt. I waited fifteen minutes and then twenty and twenty-five, and finally I left my pack and went back to look for him. It was well over an hour since I had seen him when I reached the mountaintop, and he wasn’t there. I stood confounded on the spot where we had last been together. His stuff was gone. He had obviously moved on, but if he wasn’t on Barren Mountain and wasn’t at Cloud Pond and was nowhere in between, then where was he? The only possible explanations were that he had gone back the other way, which was out of the question-Katz would never have left me without explanation-never-or that he had somehow fallen off the ridgeline. It was an absurd notion-there wasn’t anything remotely challenging or dangerous about the ridgeline-but you never know. John Connolly had told us weeks before of a friend of his who had fainted in heat and tumbled a few feet off a safe, level trail; he had lain unnoticed for hours in blazing sunshine and slowly baked to death. All the way back to the Cloud Pond turnoff I carefully surveyed the trail-edge brush for signs of disturbance and peered at intervals over the lip of the ridge, fearful of seeing Katz spread-eagled on a rock. I called his name several times, and got nothing in return but my own fading voice.

By the time I reached the turnoff it had been nearly two hours since I had seen him. This was becoming worryingly inexplicable. The only remaining possibility was that he had walked past the turnoff while I was down at the pond filtering water, but this seemed manifestly improbable. There was a prominent arrowed sign by the trail saying “Cloud Pond” and my pack had been clearly visible beside the trail. Even if he had somehow failed to notice these things, he knew that Cloud Pond was only a mile from Barren Mountain. When you have hiked the AT as much as we had, you get so you can judge a mile with considerable accuracy. He couldn’t have gone too far beyond without realizing his mistake and coming back. This just didn’t make sense.

All I knew was that Katz was alone in a wilderness with no water, no map, no clear idea of what terrain lay ahead, presumably no idea of what had become of me, and a worrying lack of sense. If there was ever one person who would decide while lost on the AT to leave the trail and try for a short cut, it was Katz. I began to feel extremely uneasy. I left a note on my pack and went off down the trail. A half mile farther on, the trail descended very steeply, almost perpendicularly, more than 600 feet to a high, nameless valley. He had to have realized by this point, surely, that he had gone wrong. I had told him Cloud Pond was a level stroll.

Calling his name at intervals, I picked my way slowly along the path down the cliff face, fearing the worst at the bottom-for this was a precipice one could easily fall down, especially with a big ungainly pack and a preoccupied mind-but there was no sign of him. I followed the trail two miles through the valley and up on to the summit of a high pinnacle called Fourth Mountain. The view from the top was expansive in every direction; the wilderness had never looked so big. I called his name long and hard, and got nothing in return.

It was getting on to late afternoon by this time. He had been at least four hours without water. I had no idea how long a person could survive without water in this heat, but I knew from experience that you couldn’t go for more than half an hour without experiencing considerable discomfort. It occurred to me with a sinking feeling that he might have seen another pond-there were half a dozen to choose from scattered across the valley 2,000 feet below-and decided in his perplexity that perhaps that was it, and tried to reach it cross-country. Even if he wasn’t confused, he might simply have been driven by thirst to try to reach one of those ponds. They looked wonderfully cool and refreshing. The nearest was only about two miles away, but there was no trail to it and it was down a perilous slope through the woods. Once you were in the woods and bereft of bearings, you could easily miss it by a mile. Conversely, you could be within fifty yards of it and not know, as we had seen at Pleasant Pond a few days before. And once you were lost in these immense woods, you would die. It was as simple as that. No one could save you. No helicopter could spot you through the cover of trees. No rescue teams could find you. None, I suspected, would even try. There would be bears down there, too-bears that had possibly never seen a human. All the possibilities made my head hurt.

I hiked back to the Cloud Pond turnoff, hoping more than anything I had hoped for in a long time that he would be sitting on the pack, and that there would be some amusing, unconsidered explanation-that we had kept just missing each other, like in a stage farce: him waiting bewildered at my pack, then going off to look for me; me arriving a moment later, waiting in puzzlement and going off-but I knew he wouldn’t be there, and he wasn’t. It was nearly dusk when I got back. I wrote a fresh note and left it under a rock in the middle of the AT, just in case, hoisted my pack, and went down to the pond, where there was a shelter.

The irony was that this was the nicest campsite I experienced anywhere along the AT, and it was the one place I camped without Katz. Cloud Pond was a couple of hundred acres of exquisitely peaceful water surrounded by dark coniferous forest, the treetops pointy black silhouettes against a pale blue evening sky. The shelter, which I had to myself, was on a level area thirty or forty yards back from the pond and slightly above it. It was practically new and spotless. There was a privy nearby. It was nearly perfect. I dumped my stuff on the wooden sleeping platform and went down to the water’s edge to filter water, so I wouldn’t have to do it in the morning, then stripped to my boxers and waded a couple of feet into the dark water to have a wash with a bandanna. If Katz had been there, I’d have had a swim. I tried not to think about him-certainly not to visualize him lost and bewildered. There was, after all, nothing I could do now.

Instead, I sat on a rock and watched the sunset. The pond was almost painfully beautiful. The long rays of the setting sun made the water shimmer golden. Offshore, two loons cruised, as if out for a spin after supper. I watched them for a long time, and thought about something I had seen on a BBC nature program some time before.

Loons, according to the program, are not social creatures. But towards the end of summer, just before they fly back to the North Atlantic, where they pass the winter bobbing on stormy waves, they host a series of get-togethers. A dozen or more loons from all the neighboring ponds fly in, and they all swim around together for a couple of hours for no discernible reason other than the pleasure of being together. The host loon leads the guests on a proud but low-key tour of his territory-first to his favorite little cove, say, then perhaps over to an interesting fallen log, then on to a patch of lily pads. “This is where I like to fish in the mornings,” he seems to be saying. “And here’s where we’re thinking of moving our nesting site next year.” All the other loons follow him around with diligence and polite interest. No one knows why they do this (but then no one knows why one human being would want to show another his converted bathroom) or how they arrange their rendezvous, but they all show up each night at the right lake at the right time as certainly as if they had been sent a card that said: “We’re Having a Party!” I think that’s wonderful. I would have enjoyed it more if I hadn’t kept thinking of Katz stumbling and gasping and searching for a lake by moonlight.