“I hope what trail we have is going in the right direction. I’m not looking forward to blazing one through the jungle,” Remi replied. “I was hoping the machetes were just for show.” Remi looked up at the sky, then at Sam. “It’s a long time before we run out of daylight—at least six hours.”

Each took a drink of water from his or her canteen, took out a machete, put it where it would be easy to reach, and then they began to drive up the trail.

For a time, Sam would periodically check his satellite phone’s GPS to be sure they were still heading in the direction they intended. The trail was winding and required steady climbing as it took them into the highlands of Alta Verapaz. Before darkness came they stopped and pitched their tiny tent, with its floor and zippered netting to keep the insects out. They cooked some dehydrated rations on a small fire and then slept. In the morning, they searched for water and found a couple of gallons that had been caught in a half-hollowed log. They filled two plastic containers, put in their military-grade purification tablets, and secured them in the back of the Jeep.

For each of the next five days they followed the same routine, checking the GPS each day to be sure they were on course. As they drove farther from the populated areas, they were surrounded by squads of chattering monkeys in the trees overhead, flocks of birds flying over at dawn and dusk, and many smaller birds that were invisible in the dense foliage calling out to one another. On the third day, the trail took them down from the crest of a high hill into a valley surrounded by smaller hills, the trail opening up to a surface that had been leveled by human activity.

There were big trees growing in places, and fallen leaves had turned to a thick humus and then become dirt, and then smaller plants had died, rotted, and then been overshadowed by taller neighbors. And even those trees had died, fallen, and rotted, several long generations of them. But the strip of land where this had happened was still flat. Remi and Sam looked at the low hills that rose on their right and then the ones on their left. They got out of the Jeep.

Sam put his compass on a level spot, raised its mirror, and used it to sight along the space at the foot of the hills on their right. “Perfectly straight,” he said.

He paced off the width of the flat space, from one hill to the one opposite. “Fifty of my paces,” he said. “Let’s try it farther along. I’ll grab the pack with the machetes and folding shovels.”