"HE SAYS HE'S NOT SURE we should do this," said my translator. "That maybe it's too dangerous."

These were unwelcome words, even more so because they were coming from Mr. Alex, a knowledgeable local we were relying on in this remote place thousands of miles from home.

I was a week into a trip through the Asmat region of the Indonesian province of Papua, on the southwest coast of New Guinea. There with a television crew, I was acting as a first-time host for a Travel Channel show called Gone Missing: Vanished in Papua, in which I planned to retrace the final journey of 23-year-old oil heir Michael Rockefeller, who disappeared there in 1961. Rockefeller had gone to collect intricate wood carvings by local artists for the Museum of Primitive Art, in New York, but as he was traveling along the coast—with Dutch anthropologist Rene Was­sing and two local guides—in a catamaran fashioned from two 40-foot dugout canoes, a large wave knocked out the motor, and the craft eventually capsized. They drifted all night, at the mercy of the currents. The next morning, with a sliver of land visible, Rockefeller, in spite of Wassing's protestations, decided to swim for it, using two empty fuel cans as floats. What happened to him next remains one of the 20th century's great unsolved mysteries. Did he drown battling the powerful Arafura Sea's tidal currents, or succumb to the sharks and crocs that inhabit the coastal waters? If he did make it to shore, was he then eaten by cannibals? Our goal was to re-create his final moments; if Rockefeller swam, so would I.

But first I needed to gather a little information. We were in Agats, population 1,100 and the regional hub of the Asmat, in the living room of Mr. Alex, a local merchant whose wife had prepared a delicious dinner for me and the other members of the crew, all from Los Angeles. There was Jeff Jenkins, 34, our longhaired and bearded executive producer; Nathanial Havholm, 38, a bespectacled and upbeat cameraman; and Dean Lee, 39, a fastidious and food-obsessed sound guy. Guiding us through it all, and translating Mr. Alex's concerns, was Rufus Boropka, a Papuan from the Mayu region, a couple hundred miles southeast of Agats. We were discussing the details of the swim when Mr. Alex spoke up.

"He says we need to be careful of—what's the word?" said Rufus. "Sharps? Is it sharps?"

"You mean sharks?" I asked him.

"Yes, that's it, sharks," he responded. "The fishes that is always eating people, right?"

Fantastic.

But in the middle of my swim the next day, any fear of sharks was supplanted by a more pragmatic concern: Could I actually make it to land? I had my doubts: The green target I'd hoped was solid ground turned out to be the ragged fringe of a mangrove swamp. I was plodding through thigh-deep water and tidal mud when the poisonous sea snakes showed up, as if on cue. The first one scared out from behind a tree to my left, behind Nat, the cameraman. Then, to the right, there was another one, ten feet in front of us.

Some long-dormant primate instinct kicked in: We took to the trees.

"I think this swim is officially over," I said.

"Agreed," said Nat. "Let's get the 'out' "—the scene-capping bit of narration—"and get back to the canoe."

"I've made it to what I thought was the shore," I was saying into the camera, swatting at mosquitoes, "but we've just encountered two water snakes, which is why I'm up in this tree." Just then, I heard a branch breaking, a man's stifled shout, and the sound of a splash.

Jeff, our producer, had fallen out of his tree.

Ahem. Take two.