“Let’s get going,” Arden said, standing up and hefting the precious backpack onto his shoulders. “If we get moving, we should be back in Iquitos by tonight.”

“Iquitos,” Frank said with a sigh. “Hot food, cold beer, showers…”

“Clean shirts, shaves…”

“Girls who wear clothes,” Theo put in with an eyebrow-waggling leer, and they all laughed.

It took only a few minutes to roll up and pack their hammocks and mosquito nets, and they were soon once again on the rough path – an old deer or capybara track, probably – that led back to the shore and the broken-down old Bayliner they had rented in Iquitos. Its outboard engine had coughed and stuttered worrisomely all the way up, and even died on them a half dozen times, but the way back would be easier. Iquitos was downriver. They could float back if they had to.

After just a few minutes, the path took them to a large, cleared, relatively orderly patch of head-high shrubs with bright, yellow-green leaves, tiny yellow flowers, and red, coffee-beanlike fruits.

At the entrance to it, Frank put up his hand. “Whoa, hold it. You know what this is, don’t you? It’s hayo. Coca. I think maybe we want to go around it.”

“Around it,” Arden said with an edge to his voice, “means around the swamps on either side of it. That’s a lot of extra ground to cover. I don’t know about you, but I’m bushed. And I want to have my dinner tonight in Iquitos. I never want to look at another piece of manioc.”

“Sure, me too, but we’re on the border of Chayacuro country here,” Frank said. “This could easily be theirs, and they’re not exactly as, shall we say, “hospitable” as our Tikuna friends. I’ve worked with them once or twice, and trust me, you don’t want to make them mad.”