The raft immediately felt more robust than Tom had expected, the sides higher too, designed for being adrift on an ocean rather than a river. He’d thought the octagonal shape might make it difficult to handle, and he imagined it spinning like a top downstream, but the flow of the river was strong enough that Sandeep and Barney found it easy to maintain a central course with their oars.

There was a slight bend ahead, and the other boat had already disappeared around it before they’d launched, but as they approached it themselves they could hear the unmistakable chatter and laughter. And as they rounded the bend, Barney started rowing furiously.

It was soon clear why. Joel’s boat had become snagged against a branch or root that arched out into the water, and it took some quick maneuvering to stop the second raft from ramming into it. Chris and Oscar were working hard to free it.

Shen shouted, “Any damage?”

“It’s fine,” said Joel. “We’ll pass you on the next bend.”

Kate turned incredulously to the rest of them. “Did I hear him right? He thinks it’s a race?” She shook her head, full of contempt.

Shen said, “I’m sure he didn’t mean it like that.” He looked at the river ahead of them, smooth and open, but containing any number of dangers in the miles ahead, and added, “I hope not, anyway.”

Sandeep looked back for a second. “Should we try to wait for them?”

A collective “No!” came straight back at him and he laughed and went back to using the oar to keep their boat steadily mid-river.

The river seemed to be made up of long stretches that were more or less straight, punctuated with shallow meandering turns, but the turns were frequent enough that for the next hour or so they never once saw Joel’s raft. It had to be reasonably close behind them, but they couldn’t even hear the others.

The rain stopped, and the humidity became even more intense. They took off their waterproof gear and dropped it into the bottom of the boat.

The number of flies and other insects buzzing around them rose steadily. The jungle was dense and unchanging. It hummed and whirred on either side, but there seemed to be an eerie peacefulness on the water itself.

The dog soon learned to stand and move comfortably among them, and seemed transfixed by the riverbanks, as if he alone could see the secrets hidden within that lush dark green. Occasionally he would bark, his nose pointed at a particular spot on the bank, and they’d all stare in vain and speculate on what he might have seen.