His wife and son were in a tent some way from the beach, where they would not be forced to witness the sad spectacle of the passing dead. But I saw the boy standing by the tent and staring at the waters anyway, while his mother lay prostrate inside. All the symbols of civilization—a picnic hamper, wine bottles, cruet sets, parasols, trunks with changes of clothes—passed before his gaze and were carried away, as if offered in sacrifice for the use of the drowned in the afterlife.

That evening, I overheard Sir Owain speaking to his wife and son. I did not deliberately eavesdrop. Voices carry through canvas, and it was impossible not to hear.

I heard him say, “We’ve suffered a setback, I won’t deny it. I cannot promise you all of the comforts I’d intended to provide. But I swear to you. Our safety is not compromised and our purpose has not changed.”

Mrs. Lancaster said something in return, and I could not hear what.

The next morning I looked out across the river and saw the head of that rocking horse floating by, upright and bobbing like a seahorse, badly battered and with its body mostly submerged in the water. In the same moment I saw that Lancaster’s boy was in the river up to his knees, trying to reach it.

I called out, “Are you mad, boy? What do you think you’re doing?” and I waded into the water and dragged him back to the shore. Though the river was slower here, it was far from safe. There were undercurrents, and there were parasites. The rocking horse was already gone.

Later that day, Sir Owain sought me out.

He said, “Simon has demanded that I dismiss you.”

I thought at first that he was making some wry comment and that thanks would follow. But then I saw that he was serious.

I said, “I beg your pardon?”

“Please,” he said. “If my son is ever to be disciplined, I’d prefer you don’t interfere.”

“I didn’t discipline him,” I said. “I pulled him from the water before he took the step that would see him drowned or carried away. If you want him to learn anything from this misconceived adventure, show him how to look after himself or teach him some gratitude.”

I cannot tell you Sir Owain’s reaction, as at that point I turned my back on him and walked away.

WITH OUR five boats, our mixed party of survivors, and our salvaged equipment, we continued down the river. In shallow water near the next night’s camp, Sir Owain spied one of his instrument cases and, seeming to forget all tragedy, exulted in the possibility that he might still achieve something of the scientific purpose of the expedition.

But when the case was recovered, everything inside proved to be smashed or damaged in some way.

“Ruined,” I heard him say. “All ruined.”

That night some animal moved through the jungle close to our camp, smashing and breaking trees. We reached for our remaining guns and leapt to our feet. But as much as we did not want to leave the light of our campfire, the intruder did not wish to approach it and we were spared a confrontation.

The next morning we contemplated its wide trail, and two of the camaradas set out to follow it. Sir Owain called me over and asked for my thoughts.

I said, “There’s no single animal of such a size. Not in this jungle. Unless the rumors are true and the Megatherium survives.”

“Megatherium?” he said. “Never heard of it. Is it a dinosaur?”

“No,” I said. “It’s one of the largest mammals ever known. Believed to have been extinct for over five thousand years, but some say that the Amazon basin is vast enough and wild enough for some areas of its ancient habitat to survive unchanged.”

“Herbivore or carnivore?”

“Herbivore,” I said. “The Megatherium’s stance was like a bear’s, but it was the size and weight of a bull elephant.”

He nodded, and kicked thoughtfully at the trampled ground, and then looked at all the stalks and branches that the creature had broken in passing.

“That could have done it, all right,” he said.

“Could have,” I said. “If one even exists.”

“What do you think, Somerville? What if a man could bag such a beast and drag it home?”

He was serious. I thought for a moment that he was speaking hypothetically, but he was not.

I said, “Owain. Look at what’s been lost. Forget about your standing and your reputation for once. We’ll be lucky if we all survive.”

He narrowed his eyes and looked at me. With the manner of a man who is judging what he’s looking at, and thinking little of what he sees.

He said, “Don’t make me regret bringing you along, Doctor Somerville. You can be such an old woman sometimes.”

THE TWO camaradas did not return. I have no idea why, and nor did anyone else. I don’t believe that they ran away. It made no sense for them to leave the boats. Without the river there was little chance of crossing this jungle and surviving the journey.

Sir Owain talked about going after them, not for the sake of the men but for the beast they’d followed. If he could not bag it alive, he’d have a trophy. I could see that he’d begun to look for some outcome, any outcome, that might save his face and justify his losses on our return to civilization. He was probably writing the Royal Society speech in his head. My dear lost colleagues and loyal servants, I mourn them all; and I dedicate this triumph to their memory.

Meanwhile, his son had begun to suffer painful eruptions on his bare legs. Though he’d dubbed me the party’s physician, Sir Owain had now started to behave to me as he behaved to all critics, by sending the odd sarcastic shot in my direction (“We might have some tea, if Doctor Somerville doesn’t think it too dangerous,”) but otherwise choosing largely to ignore my existence. He said to his son, “It’s just bug bites, boy. Get some lotion on them and stop your complaining,” and so the boy came to me on his own.

He stood by me and said, “Excuse me, sir,” and I hadn’t the heart to let the rocking horse incident color my response.

I’d heard the conversation with his father and so I said, “Hello, Simon. Need something for those bites?”

“Father’s told me to get some lotion.”

I looked at his legs. I saw no bug bites. Just infected scratches. In these conditions he should have been in long trousers from the beginning, regardless of youth and social convention.

“Let’s see what there is for you,” I said.

There was nothing. Someone had been at my kit, and anything that might have been useful was gone. The boy was watching me now, and I didn’t want to turn him away without at least making some effort to help him.

Then I had an inspiration and took out my hip flask. I soaked a pad in neat navy rum, and said, “Some of those wounds are quite raw, so I can tell you this will sting. But in a good way. Have you been scratching them?”

“A little,” he admitted.

“I know,” I said, “it’s hard not to. We’ll bind them up to stop them itching and give them a chance to heal.”

I swabbed his wounds with the rum, which I know must have hurt, but he remained stoical and barely made a sound. Then I tore up some linen and bound his legs in makeshift puttees. They probably wouldn’t help with the itching, but they would protect his legs and prevent him from making the scratches worse.

For the rest of the day he followed me around, offering to help with whatever job I was doing.

DISASTER STRUCK again the next morning, within an hour of continuing our journey. Our river merged with a second, faster torrent, and our pilot boat was capsized in the crosscurrent. Sir Owain, his wife, his son, the Indian, the astronomer, and two of our surveyors were dumped into the foam, along with the paddle crew. The boat was lost, but all swam to safety, or were rescued.

Which in itself would have been a comparatively happy outcome, had the boy not been dragged from the shallows unconscious. A first examination found no visible harm. But when his shirt was opened, a spreading contusion under the skin below his ribs signaled some profound hidden injury.