He looked at the ground, and sighed. Then he accepted the flask and took a hefty swig. He made a face as the rum went down. “You were right to be hard on me,” he said, offering it back. “I should never have brought them here. What was I thinking?”

“You were thinking that all the world must be tameable,” I said, waving the flask away, “because you’d already succeeded in taming so much of what you could reach.”

“No,” he said. “I truly believe there’s a malevolence at work. They were taken. This jungle took them.”

“Yes, Owain,” I said, because there’s no arguing with the deluded. “And nothing can bring them back. So now we have to look to the welfare of the survivors. Tell me. How did you manage to hide the boats?”

“I didn’t,” he said.

“Oh, come on,” I said. “For boats that aren’t hidden, you concealed them very well. Some of the men have been sneaking off and scouring the riverbank for as far as they could walk. Not one of them’s found a sign.”

Sir Owain just sat there looking at me, and offered no explanation. Suddenly I understood. Or believed I did.

“You sank them, didn’t you?” I said. “They’re sitting out there on the riverbed waiting to be raised and refloated. You crafty dog.”

But I saw nothing in Sir Owain’s eyes.

“Well?” I prompted.

He said, “I untied the lines, and shoved the boats out into the river where they were carried off.”

Was he joking? Surely he was joking.

He was not.

“They’re gone?” I said.

He shrugged. “I wish I’d thought of your bottom-of-the-river trick,” he said, and tilted his head back with the flask tipped high, his Adam’s apple bobbing as he downed the rum like so much water.

I persisted.

“So we have no boats,” I said.

“No,” he said.

WHEN I AWOKE the next morning, it was to find our campfire extinguished and our camp deserted. Europeans, Indians, camaradas … all were gone. They had taken what remained of the supplies, and abandoned us.

Over in his tent Sir Owain slept on, snoring in a noisy rum coma, much as I’d left him the night before. After a sleepless week, the liquor had kicked away his supports and he’d fallen hard.

Now this. Our situation was bleak. I contemplated my own with dismay. The others had seen me as Sir Owain’s man, to be abandoned along with him. Such were the consequences of my caution and sympathy. I picked my way around what remained of our camp, looking for anything useful that the others might have left behind. When I came to the grave site, an appalling spectacle awaited me.

The stone tomb, so carefully and solidly built, had been pushed over by some terrible force. How had I slept through this? The slab had tipped and its walls had fallen, and the rotted bodies had been dragged out onto open ground and mauled.

At least, I believe they’d been mauled. I am no expert in the work of explosive decay.

Their canvas shrouds had been ripped head to toe. Surely the others had not done this out of spite before they left? Although as an explanation, it did occur to me before any other. But the force of it, and the fury.…

I felt helpless. What was I to do? Take my own chances in the jungle, and leave Sir Owain to make this discovery alone?

I had intended to walk away. My alternative was to stick with a madman, which would mean facing the odds with an added handicap. I’d be like a conjoined twin in a drowning pool, with the weight of a dead brother pulling him down.

Then from behind me I heard, “Holy mother of all mercy,” and I knew that my opportunity to choose had already gone.

Sir Owain had risen, and came to stand beside me now. He did not blink or look away; he bore the unbearable.

We could not think of restoring the tomb. Between us we had not the necessary strength, and besides, it was irreparable. One of the side slabs was cracked, and the other completely broken. We remade the shrouds as best we could and dragged the bodies back to their hole. We placed flowers in the grave all around them and then piled on every one of the stones that we could move, plus a few more from the river. This time there was no service, no ceremony.

After that, with only the clothes we stood up in, we set off to follow the river onward as best we could and eventually, God willing, to walk out of the jungle.

WE KNEW OF only one reliable food source. Like our Indians, we were reduced to cutting into flowering bamboo and eating the grubs we found inside. Though trained in botany and able to identify some of the more extreme poisons, I had little useful knowledge that I could apply to living off the land. Disgusting though the bugs were—and we ate them alive—they sustained us and did us no harm. Whereas our one experiment with berries left us violently sick and shaking for most of a day.

Though some of the time he’d walk along for hours in an introspective silence, at his worst Sir Owain was a raving companion. At night, he would pick out sounds and identify them with total certainty as the cries of beasts that were calling to one another, plotting to capture us. By day he’d point to their traces, which I actually believe to have been made by some of our former companions moving ahead of us. It seemed only logical to assume that they would be following the river, as we were.

One time, as we rested in exhaustion after a hazardous descent beside a waterfall, Sir Owain suddenly gripped my arm and pointed across the river, saying, “See. There one goes.”

All I could see was the fog of spray at the base of the falls, and the rainbow that it made.

“I see nothing,” I said.

“I see the spaces where they’ve been,” he said. “The space retains the shape. Until it fades.”

Make of that what you can.

I began to understand why our Indians had turned so lazy. The bamboo grubs, which habit made easier to stomach as the days went by, inclined us to lethargy and fueled the most strange and vivid dreams. Taken early in the day, they induced a daze that lasted for hours. One time I stepped on a sharp rock and did not realize until much later that it had split my boot and my foot was bleeding badly.

At night, we’d pile up fronds to make a bed. Sleep came easily. Exhaustion and bamboo grubs saw to that. One morning, at daybreak, I awoke to find Sir Owain shaking me.

“Bernard,” he said, using my given name for only the second time. “I’ve done it. I’ve killed one.”

I blinked and yawned and raised myself. “What do you mean?”

“I followed it and killed it. Look.”

He showed me his hands. There was blood on them. On his hands, on his clothes, everywhere. And on my arm, where he’d touched it.

I said, “Show me.”

He led me down to the riverbank. I was limping. It was the start of an infection that would come close to losing me a leg.

Sir Owain was chattering away.

“I saw its eyes before anything else,” he said. “They were yellow. And they shone, Bernard. Lit from within. I swear to you they shone like lanterns!”

Pain lanced up my leg from my wounded foot as I tripped over his hunting rifle. The weapon was lying in my way, discarded and undischarged. Had he fired a shot during the night, bug juice or no bug juice, I’m sure the sound of it would have woken me.

“Owain,” I said, “look at me.”

He stopped. I looked into those eyes and saw a man lost in madness.

“It was there, Bernard,” he pleaded. “It was as real as you are. It’s like nothing you’ve ever seen. Please. I can prove it to you.”

We came to a clear and level spot by the river. There we found a half-built raft, and three of our former companions. The astronomer, our cartographer, and one of the Portuguese laborers. All slaughtered. They’d been hacked down and cruelly cut about. In places their wounds were to the bone. Close by lay a machete knife. They’d been using it to build the raft and I was almost certain it was the instrument that had cut them down.