As soon as Erika climbed into the plane, Ben slammed his foot into the accelerator. The WASP skidded across the bumpy earth, swerved from side to side, then stopped with a sudden jolt.

Ben looked at his sister’s shocked face and burst out laughing. “Just kidding,” he said with a grin. “You should see your face, though!”

Zoe playfully socked Ben in the arm. “Jerk,” she said.

Ben accelerated again, this time steering the vehicle slowly and expertly between the small boulders that littered the hard, red earth. Already the temperature was rising. Zoe and Ben pulled on their hats with flaps that covered their necks.

“Look!” Zoe said. “There’s something moving over there.”

Zoe set her glasses to full zoom.

“Hyenas,” Zoe said. “There’s no mistaking the way they hunch their backs. We should stay away from them.”

Ben nodded. He steered the WASP around a group of scraggly brown trees that were topped with small yellow leaves. “Check those out!” he said. “I read about them on the plane. They’re elephant’s trunk plants.”

Ben wove between low plants and sparse patches of grass.

“This is a very strange place,” said Zoe. “There’s more vegetation than I expected.”

The sun rose in the sky. A light breeze blew up. “Time to raise the sails!” said Ben.

“Don’t worry,” Zoe said. “The expert’s here to handle it.”

Ben gave her a mocking salute. “Aye, aye, Captain!” he said.

Ben brought the WASP to a stop and flicked a switch to turn off the engine. Zoe climbed into the driver’s seat and released the sail. It billowed out and caught the wind immediately. Soon the WASP was sailing from side to side across the sand.

“Awesome!” yelled Zoe. “It’s almost as fun as real sailing.”

“Better than real sailing!” Ben yelled back. He checked the map, holding tightly to his BUG as they jolted along. “We’re almost there. Just another mile or so.”

“There’s a hollow up ahead,” said Zoe, peering out over the shimmering landscape. “And I can hear goats.”

“We’d better check it out,” said Ben. “There could be people looking after their herds down there. If so, we’ll have to change our route so they don’t see us.”

“Agreed,” said Zoe. “Two children traveling on their own out here? They’d definitely try to stop us. They wouldn’t know we’re on a vital mission or that we have the skills to survive here.”

“And we couldn’t tell them,” said Ben. Zoe nodded.

Zoe let the sail flap loose as Ben braked. The buggy came to rest behind a clump of thorny bushes.

They climbed out and crept across the hot sand to where the land dipped away. Using the bushes and grass as cover, they were able to glance down at a herd of goats in the valley below. They were grazing while being watched over by two small figures.

“They’re just kids,” said Ben. “Let’s go talk to them.”

“Do you think we should?” Zoe asked. “After all, we don’t want to attract attention to ourselves.”

“Maybe they know something useful,” said Ben. “They probably know about the well we’re looking for. They might even be able to tell us if the lioness is still there.”

“Then we’ll have to put translators in so we can understand everything they say,” said Zoe. She peeled off the small rubber earpiece from the side of her BUG and popped it into her ear.

Zoe scrolled through the menu of her BUG. “I looked it up on the plane,” she said. “They speak a form of click language called Nama, although many Namibians speak English too.” They both found Nama and entered it into the translator.

“All right, let’s go,” Ben said. They slipped their BUGs into their pockets and walked toward the grazing herd. The two children stood together. One was a girl a little younger than Ben and Zoe. Her hair was tightly woven into braids, and she wore a bright red T-shirt over a wraparound skirt.

The other goatherd was a boy who seemed to be around five years old. The girl held a long spear in her graceful hand.

“Hello!” Ben called as he and Zoe approached. The goatherds looked up and stared at them.

“Can you help us?” Zoe asked slowly. “We are visitors in your country.”

The two goatherds glanced at each other but didn’t speak.

“We’ve traveled a long ways,” said Ben. “We are thirsty.” He clutched his throat and stuck out his tongue. “Water!”

The girl took a jar that was bound in cowhide from her belt. Without a word, she handed it to Ben.

“Thank you,” he said, taking a small sip.

Then he handed it to Zoe who did the same. Asking for a drink was a good excuse to talk to the two kids, but Ben and Zoe didn’t want to leave them short of water in this hot, dry landscape. Ben dug through his backpack and pulled out two of Uncle Stephen’s special energy bars. He passed them to the girl, who inspected them.

“Cherry,” she read slowly.

“You speak English?” said Zoe.

The girl nodded. “A little,” she said. “But my brother doesn’t.” She handed a bar to the little boy, who unwrapped it quickly and began to eat.

The boy turned to his sister. “I like it,” he said in his own language. Ben and Zoe had to pretend they didn’t understand.

The boy smiled brightly at them, nodding his head and rubbing his tummy.

Ben and Zoe smiled and grinned back. “I’m Ben,” Ben said. “This is my sister, Zoe.”

“My name is Tukwenethi,” said the girl. She waved a hand toward her brother. “And this is Jossy.”

“Thank you for the water,” said Zoe, handing back the bottle. “Is it from a well or a pool?” she added. Ben smiled. That was a clever way for Zoe to ask for information about the well, he thought. They won’t suspect anything.

“All our water is from wells,” said Tukwenethi. She pointed to the north. “There is a pool there, but it is bad water. It makes people sick. Only animals drink from it.”

“Is your well far away?” asked Ben.

“Not far,” Tukwenethi said. “About two hours’ walk. But we cannot use it. There is a lion mother there and she will not let us get near. Now we have to go to the next well. It is a day’s walk away.”

Jossy pulled at his sister’s arm. In their language, she told him what she had said.

Jossy’s eyes widened. “There’s a ghost in the well!” he said. His translated words rang in Ben and Zoe’s earpieces. “It moans and cries out. Mommy said someone went there last night and it was still there. I would be brave and fight a lioness, but not a ghost.”

Ben gave Zoe a knowing glance. The cub was alive!

Jossy spun around and stared up at the far side of the hollow. Now Ben and Zoe could hear something too. Adult voices, speaking in Nama. And they seemed to be coming closer.

Ben and Zoe looked at each other in alarm. They had to disappear — and quickly!