Hawk asked, “What’s an ice age?”

“It’s what follows a greenhouse warming. This greenhouse was an anomaly, caused by anthropogenic factors. Now the CO2’s being leached out of the atmosphere and the global climate will bounce back to a Pleistocene condition.”

He might as well have been talking Cherokee or some other redskin language, Tim thought. Hawk looked just as baffled.

Seeing the confusion on the boys’ faces, the Prof went to great pains to try to explain. Tim got the idea that he was saying the weather was going to turn colder, a lot colder, and stay that way for a really long time.

“Glaciers a mile thick!” the Prof said, nearly raving in his earnestness. “Minnesota, Michigan, the whole Great Lakes region was covered with ice a mile thick!”

“It was?”

“When?”

Shaking his head impatiently, the Prof said, “It doesn’t matter when. The important thing is that it’s going to happen all over again!”

“Here?” Tim asked. “Where our folks live?”

“Yes!”

“How soon?” asked Hawk.

The Prof hesitated. He drummed his fingers on the desktop for a minute, looking lost in thought.

“By the time you’re a grandfather,” he said at last. “Maybe sooner, maybe later. But it’s going to happen.”

Hawk let a giggle out of him. “That’s a long time from now.”

“But you’ve got to get ready for it,” the Prof said, frowning. “It will take a long time to prepare, to learn how to make warm clothing, to grow different crops or migrate south.”

Hawk shook his head.

“You ought to at least warn your people, let them know it’s going to happen,” the Prof insisted.

“But we’re headin’ for Colorado,” Tim confessed. “We’re not goin’ back home.”

The Prof’s bushy brows knit together. “This climate shift could be just as abrupt as the greenhouse cliff was. People who aren’t prepared for it will die—starve to death or freeze.”

“How do you know it’s gonna happen like that?” Hawk demanded.

“You saw the satellite imagery of Canada, didn’t you?”

“We saw some picture of something, I don’t know what it really was,” Hawk said. “How do you know what it is? How do you know it’s gonna get so cold?”

The Prof thought a moment, then admitted, “I don’t know. But all the evidence points that way. I’m sure of it, but I don’t have conclusive proof.”

“You don’t really know,” Hawk said.

For a long moment the old man glared at Hawk angrily. Then he took another deep breath and his anger seemed to fade away.

“Listen, son. Many years ago people like me tried to warn the rest of the world that the greenhouse warming was going to drastically change the global climate. All the available evidence pointed to it, but the evidence was not conclusive. We couldn’t convince the political leaders of the world that they were facing a disaster.”

“What happened?” Tim asked.

Spreading his arms out wide, the Prof shouted, “This happened! The world’s breadbaskets flooded! Electrical power distribution systems totally wiped out. The global nets, the information and knowledge of centuries—all drowned. Food distribution gone. Cities abandoned. Billions died! Billions! Civilization sank back to subsistence agriculture.”

Tim looked at Hawk and Hawk looked back at Tim. Maybe the old man isn’t a witch, Tim thought. Maybe he’s just crazy.

The Prof sighed. “It doesn’t mean a thing to you, does it? You just don’t have the understanding, the education or . . .”

Muttering to himself, the old man turned back to his magic box and pecked at the buttons again. The picture went back to the first one the boys had seen.

Abruptly the Prof jabbed a button and the picture winked off. Pushing himself up from his chair, he said, “Come on, we’ve got to get your boat farther up out of the water and tied down good and strong.”

“What for?” Hawk demanded, suddenly suspicious.

With a frown, the Prof said, “This area used to be called Tornado Alley. Just because it’s covered by water doesn’t change that. In fact, it makes the twisters even worse.”

The boys had heard of twisters. One had levelled a village not more than a day’s travel from their own, only a couple of springtimes ago.

When it came, the twister was a monster.

The boys spent most of the day hauling their boat up close to the trees and then tying it down as firmly as they could. The Prof provided ropes and plenty of advice and even some muscle power. All the time they worked the clouds got thicker and darker and lower. Tim expected a thunderstorm any minute as they headed back for the Prof’s house, bone tired.

They were halfway back when the trees began tossing back and forth and rain started spattering down. Leaves went flying through the air, torn off the trees. A whole bough whipped by, nearly smacking Hawk on the head. Tim heard a weird sound, a low dull roaring, like the distant howl of some giant beast.

“Run!” the Prof shouted over the howling wind. “You don’t want to get caught here amidst the trees!”

Despite their aching muscles they ran. Tim glanced over his shoulder and through the bending, swaying trees he saw a mammoth pillar of pure terror marching across the open water, heading right for him, sucking up water and twigs and anything in its path, weaving slowly back and forth, high as the sky, bearing down on them, coming to get him.

It roared and shouted and moved up onto the land. Whole trees were ripped up by their roots. Tim tripped and sprawled face-first into the dirt. Somebody grabbed him by the scruff of his neck and yanked him to his feet. The rain was so thick and hard he couldn’t see an arm’s length in front of him but suddenly the low earthen hump of the Prof’s house was in sight and the old man, despite his years, was half a dozen strides ahead of them, already fumbling with the front door.

They staggered inside, the wind-driven rain pouring in with them. It took all three of them to get the door closed again and firmly latched. The Prof pushed a heavy cabinet against the door, then slumped to the floor, soaking wet, chest heaving.

“Check . . . the windows,” he gasped. “Shutters . . .”

Hawk nodded and scrambled to his feet. Tim hesitated only a moment, then did the same. He saw there were thick wooden shutters folded back along the edges of each window. He pulled them across the glass and locked them tight.

The twister roared and raged outside but the Prof’s house, largely underground, held firm. Tim thought the ground was shaking, but maybe it was just him shaking, he was so scared. The storm yowled and battered at the house. Things pounded on the roof. The rain drummed so hard it sounded like all the redskins in the world doing a war dance.

The Prof lay sprawled in the puddle by the door until Hawk gestured for Tim to help him get the old man to his feet.

“Bedroom . . .” the Prof said. “Let me . . . lay down . . . for a while.” His chest was heaving, his face looked gray.

They put him down gently on his bed. His wet clothes made a squishy sound on the covers. He closed his eyes and seemed to go to sleep. Tim stared at the old man’s bare, white-fuzzed chest. It was pumping up and down, fast.

Something crashed against the roof so hard that books tumbled out of their shelves and dust sifted down from the ceiling. The lights blinked, then went out altogether. A dim lamp came on and cast scary shadows on the wall.

Tim and Hawk sat on the floor, next to each other, knees drawn up tight. Every muscle in Tim’s body ached, every nerve was pulled tight as a bowstring. And the twister kept howling outside, as if demanding to be allowed in.