“We're in one piece. That's more than I can say for Dieter and his friends.”

“The men of the tribe brought the heads back as gifts to me.” She glanced around the dining room which was hung with colorful tapestries of village life. “Shrunken heads would clash with my decor, so I suggested they put them outside the village.”

“Were you also responsible for our welcoming committee?”

“Oh, yes. You must admit that big orange-and-blue balloon you were flying was not inconspicuous. The men reported that you had almost flown into the falls. I had ordered that if you were seen you would be observed but not harmed. They were tracking you from the start. I was surprised when you started this way. You couldn't have been lost.”

“We thought we might borrow a canoe.”

“Ah. How audacious! You wouldn't have stood a chance. The reputation these people have is well deserved. They tracked you for miles. Sometimes I think they truly are the ghost people. They can melt through the forest like the mists the other Indians say they are made of.”

Paul had been pondering Francesca's story. “Why would someone want to hijack the plane and kidnap you?”

“I have an idea why. Come, I'll show you.”

Francesca rose from the table and led the way through torch lit hallways to a large bedroom. She reached into a chest and pulled out a battered and scarred aluminum case. She set it on top of her bed, then opened it. Inside was a jumble of broken wires and circuits.

“This was a model of the experiment I was carrying to Cairo. I won't go into the technical details, but if you pour seawater in on this end, the salt is extracted and fresh water comes out here.”

“A desalting process?”

“Yes. It was a revolutionary approach unlike any devised before. It took me two years to perfect. The problem with desalination has been its cost. This process would transform hundreds of gallons for only pennies. At the same time it produces heat which can be transformed into energy.” She shook her head. “It would have turned deserts into gardens and allowed people the benefits of power.”

“I still don't understand,” Paul said. “Why would someone want to prevent a boon like this from being made available to the world?”

“I've asked myself that question many times in the past ten years and still have no satisfactory answer.”

“Was this your only model?”

“Yes,” she said sadly. “I took everything with me from Sao Paulo. All my papers were burned in the plane crash.” Brightening, she said, “I was able to put my hydraulic engineering skills to work here. It can be boring just sitting around being adored all day. I'm virtually a prisoner They hid me from search parties after the crash. The only place where I am truly alone is this palace. Only those who are invited can enter. My servants were handpicked for their loyalty. Outside the palace I'm watched by my Praetorian guard.”