“Back to Timbuktu,” said Hopper firmly. “Did you notice the look on people we interviewed before setting out to the south? They were nervous and worried. You could see it in their faces. It’s just possible they were threatened to keep silent.”

“Especially the Tuaregs from the desert,” recalled Grimes.

“You mean especially their women and children,” Eva added. “They refused to be examined.”

Hopper shook his head. “I’m to blame. I made the decision to turn our backs on the desert. It was a mistake. I know that now.”

“You’re a scientist, not a psychic investigator,” Grimes consoled him.

“Yes,” Hopper agreed readily. “I’m a scientist, but I hate being made the fool.”

“The tip-off we all missed,” said Eva, “was the patronizing attitude of Captain Batutta.”

Grimes looked at her. “That’s right. Oh-ho. You’ve struck oil again, my girl. Now that you’ve brought it up, Batutta has been downright servile with cooperation.”

“True,” Hopper nodded. “He’s leaned over backward in allowing us to go our merry way, knowing we were hundreds of kilometers off the scent.”

Grimes finished off his soda water. “Be interesting to see the look on his face when you tell him we’re going out in the desert and start from scratch.”

“He’ll be on the radio to Colonel Mansa before I get the words out of my mouth.”

“We could lie,” said Eva.

“Lie, for what reason?” asked Hopper.

“To throw him off, to throw them all off our trail.”

“I’m listening.”

“Tell Batutta the project is finished. Tell him we’ve found no sign of contamination and are returning to Timbuktu, folding up our tents and flying home.”

“You’ve missed me. Where is this leading?”

“For all appearances the team has quit, given up,” Eva explained. “Batutta waves a relieved farewell as we take off. Only we don’t fly to Cairo. We land in the desert and set up shop again on our own without a watchdog.”

The two men took a few seconds to absorb Eva’s scheme. Hopper leaned forward, intently mulling it over. Grimes looked as if someone asked him to catch the next rocket to the moon.

“It’s no good,” Grimes said at last, almost apologetically. “You can’t just land a jet aircraft in the middle of the desert. You need a runway at least 1000 meters long.”

“There are any number of areas in the Sahara where the ground is perfectly flat for hundreds of kilometers,” Eva argued.

“Too risky,” Grimes said stubbornly. “If Kazim got wind of it, we’d pay dearly.”

Eva looked sharply at Grimes, then more slowly at Hopper. She detected the beginnings of a smile on Hopper’s face. “It is possible,” she said firmly.

“Anything is possible, but often not practical.”

Hopper smashed his fist down on the arm of his camp chair so hard he nearly broke it. “By God, I think it’s worth a go.”

Grimes stared at him. “You can’t be bloody serious?”