He trekked back to the river and saw boot prints along the edge leading into the interior. His practiced eye picked out five different sets of boot prints, including two smaller, less deep ones that looked as if they belonged to women. He felt less tired, energized by the prospect of a reunion with his goddaughter, and began to pick up his pace. Some time later, Schroeder's elation changed to alarm.

Heavy boot tracks obliterated the others. Karla and her party were being stalked.

NUMA 6 - Polar Shift

23

FROM THE TOP OF the knoll she had climbed, Karla could see that Ivory Island was not the arctic desert she had first assumed it to be. The tundra was treeless, but it was thick with low-lying, dwarf shrubs, grasses, mosses and sedges that formed a muted carpet. Dandelions, buttercups and fireweed created vibrant splashes of color. The morning sunlight glittered on distant lakes and rivers. Noisy seabirds wheeled overhead.

In her mind's eye, she pictured the rugged landscape as verdant grassland, the steppes teeming with vast herds of woolly mammoth. There would have been bison and woolly rhinos, giant ground sloths, all stalked by predators like the scimitar or saber-toothed cats. She could almost smell the musky animal odor and feel the ground shake from the passage of thousands of huge animals.

Somehow, as if an evil sorcerer had waved a magic wand, the mammoths and the other creatures had became extinct. The question of extinction had intrigued her as far back as she could remember. Like many children, she had been fascinated by dinosaurs and the great mammals that succeeded them as the earth's masters.

Her grandfather was the only scientist she knew, so of course she went to him and asked what had caused these magnificent creatures to die. She had listened wide-eyed as he explained how the world had shifted, and asked him if it could happen again. He had said yes, and she had been unable to sleep. Seeing her fear, a few nights later he had taught her a nursery rhyme that would make the topsy-turvy world right again. She was trying to dig the rhyme from her memory when she heard someone shout.

“Karla!”

MARIA ARBATOV was waving her arms at Karla. The expedition was ready to get moving again. Karla started walking back to rejoin the others. It was time to return to the task at hand. She knew it would not be easy. The discovery of the baby mammoth carcass had been an astounding stroke of luck. But Ivory Island was a rich trove of the ancient past. If she couldn't find what she wanted here, she should forsake field trips forever and stick to cataloging museum specimens.