Light pulsed.

The white-hot rock fragment was just a scrap. After the encounter with the whale it continued its descent toward the thick Cretaceous forests, only a fraction of its kinetic energy expended. But the whale’s complex nervous system brought his small brain messages of agonizing pain. When he turned his great head to the right, he saw that the surface of his wing was torn and scorched.

If the meteor had hit near the center of the wing, it might have made no more than a puncture, and the whale might have lived a little longer. But the whale had been unlucky. The meteor had punched through the joint of an immense, fragile flight finger. The wing began to fold up in great sections around the broken segment of bone.

The blue-gray Earth tipped over. Though he thrashed inelegantly with his good wing, the whale was already falling away from the horizontal — falling out of control, out of the sky. Still he remained conscious, slowly twisting, crumpling like a broken toy kite. But the meteor hail thickened. Bulletlike meteors tore tunnels through the fine caverns of his body, ripping open air sacs, smashing his delicate, light-as-air filigree skeleton, further puncturing his magnificent wings.

The pain became overwhelming. His mind filled with comforting, creamy memories of gliding high over an undisturbed Earth. He died long before the remnants of his torso reached the ground, his lungs crushed by the thick air.

Giant was struggling to get back to his feet.

Before him a stegoceras lumbered, bewildered, the scarlet-coated cap of bone and flesh on his head absurd. Thanks to a chance sheltering in a dense crop of araucaria this young male had survived the tornado, suffering no worse injury than a snapped rib. But his clan was gone, scattered by the wind. He lifted his head and howled, a great mournful lowing. It was like a chick’s call of distress, a lost call.

It wasn’t his mother who responded, but two huge carnivores, giganotosaurs, who came stalking slowly toward him, their heads bobbing, their eyes fixed on him. Even now, the game of predator and prey continued.

But through the adrenaline-induced fear that flooded his system, the stegoceras noticed something strange. A third giganotosaur, as big and powerful as the rest, was showing no interest in him. The third monster was head-bobbing, threatening, reacting to something that approached from out of the sky. Confused, fearful, the stegoceras turned to the south, where a lowering cancerous orange continued to spread through the racing black clouds.

The first meteor screamed overhead like a glowing hornet. It flew low over the smashed forest and slammed against a foothill beyond. Young volcanic stone exploded, and a secondary shower of steaming fragments hailed out, pattering against the debris-strewn ground. All the dinosaurs turned that way, shocked and startled, their innate animosity briefly forgotten.

And the second meteor passed through the stegoceras’s body, like a high-velocity bullet. A fraction of a second later, on meeting the impenetrable ground, the meteor dumped the last of its energy into the rock. The explosion burst apart the stegoceras’s body before it had time to fall. In the brief rain of blood, Giant cringed, uncomprehending.

Now the meteors began to land in the remains of the smashed forest. Fire splashed.

Giant and his brothers panicked and ran. But still the meteor rain thickened. The meteors pounded the ground around the giganotosaurs, digging shallow craters and starting fires even in the scattered undergrowth. It was as if the brothers were running through an artillery barrage.

Purga, too, could smell the smoke.

The primates could ride out fires in their burrows, buried deep in the cool earth, to emerge into the debris of a charred and ruined forest. But, Purga’s instincts warned her, this time was different. She pushed past her cowering mate and her pups, past the grisly severed head of the troodon. She emerged into daylight. She was immediately dazzled, her sensitive night-adapted eyes unable to cope with the unaccustomed flood of light. But she could nevertheless make out the main features of the terrible day: the spreading fires in the smashed blanket forest, the continual, incomprehensible rain of meteors.

She could not stay here. But where to go?

With much of the obstructing forest already demolished by the winds she could see the shoulders of the Rockies with their clouds of volcanic smoke lingering at their summits. And where the comet winds had pushed warm, moist air up the flanks of the rising ground, thick cumulus clouds clung to the mountain’s upper slopes.

Shade. Darkness. Perhaps there would even be rain.

She took a step further into the open, whiskers twitching. She moved in rapid jerks, pausing every few paces, flattening herself against the ground.

She looked back. Beyond the fallen head of the troodon, she could see her mate and pups, three sets of wide eyes peering after her. Instincts honed across a hundred million years urged her to return to the cool earth, or to clamber into the trees where she would find safety, for otherwise the terrible claws and teeth and feet of this giant world would surely claim her. But the trees were smashed and broken, her burrow no longer a sanctuary.

She scurried away, toward the cloud-draped mountains.

Her mate followed, more cautiously. One of the pups followed him. The second, terrified, bewildered, bolted back into the recesses of the burrow. There was nothing Purga could do for the second pup. She would never see him again.

So the three tiny, shrewlike creatures — carrying all the potential of mankind within them — made their way slowly across the battered, smoldering plain while meteors rained around them.

The fire fed on itself. The scattered pockets of fire were beginning to link up. As the temperature of the air rose even the damp undergrowth was starting to burn. A wind began to gather, the smoke to spiral overhead. Here, and all over North and South America, the fires began to exert a logic of their own, becoming self-feeding, self-perpetuating systems.

Thus the firestorms began. Everything that could burn did so: every scrap of vegetation, even lake plants still soaked from their immersion. Animals simply burst into flame: Raptors burned like saplings and great armored herbivores cooked in their own monstrous shells.

The three giganotosaurs burst at last from the forest. They had come to a clearing centered on a large lake. They were overheated, their great mouths gaping, their heads filled with the stink of the smoke.

The open sky was extraordinary. A lid of blackness was rushing up from the southeast, as if a great curtain were closing. That eerie orange glow was spreading too, growing brighter and ascending to yellow. And still the meteors hammered into the muddy ground.

Near the lake itself a desolate scene greeted the giganotosaurs.

Dinosaurs stampeded. Great herds of rival duckbill species mingled, armored beasts like ceratops and ankylosaurs jostled for room, herbivores ran alongside giant predators. There were even mammals, blinking in the light, running amidst giant feet. All the animals charged in panic, their feet burned by the smoldering ground, clattering into each other blindly. This would have been unimaginable just a couple of hours ago. The intricate ecological relationships of herbivores and carnivores, of predators and prey, built up over a hundred and fifty million years, had utterly collapsed.

Giant pushed forward, barging his way through the panicking mob, driven to the water by a deep instinct. He plunged into the lake, ignoring the smoldering debris that floated on the surface. The deeper layers were still blessedly cool. But even with his head submerged he could see more meteors hitting the lake, creating bubble trails in the water like bullets.