Seconds later, the high-pitched whine became audible on the ground.

“Move!” Gregorovich ordered.

In seconds, the snowmobiles were firing up, but they were almost too late. The group of hovercraft came charging up the slope, appearing out of the snowy haze like avenging ghosts.

Kurt and Hayley jumped on their machine. “Hang on!” Kurt shouted as he pressed the starter and twisted the throttle.

She clung to him as the snowmobile leapt forward. The rest of the group scattered in different directions like a herd of gazelles set upon by lions. It was an unplanned tactic, but it was effective. There were six snowmobiles but only four hovercraft. Not all of them could be followed.

Racing down the slope and cutting around a snowdrift, Kurt glanced over his shoulder, looking past Hayley. Unfortunately, one of the sleek predatory craft was hot on their tail.

“Hang on tight!” he shouted. “This is going to get rough.”

He turned his eyes forward, pinned the throttle full open, and began weaving back and forth across the snowfield. If there had been a forest on the island, he would have driven straight for it, but Heard Island was treeless, a fact that didn’t bode well in terms of finding a spot to hide.

He cut to the right and caught sight of a small explosion from the corner of his eye. He avoided it and cut back to the left, only to see another one.

There was no sound to accompany the phenomenon, no concussion wave or smoke. In fact, the display looked more like the blurred pattern one sees out behind a running jet engine.

“Is that what I think it is?”

“Flash-draw,” Hayley yelled. “Stay out of it.”

“Sound advice,” he said.

They continued on at breakneck speed, and Kurt strained to see details of the near-featureless terrain streaking past him. Even with the goggles, the light was so flat it was almost impossible to spot dips and rises. Twice, uneven sections of the ground almost tipped them over, and then suddenly they were airborne, flying off the crest of a small ledge.

The snowmobile caught air at forty miles per hour, dropped about five feet, and landed solidly on the downslope like a contestant in the X Games.

Kurt’s chin hit the windshield, gashing it and jarring him, while Hayley’s boa-constrictor-like grip around his waist kept her on board.

The hovercraft launched itself over the same ridge without any hesitation. It dropped and landed smoothly on its cushion of air without any hint of the jarring impact Kurt and Hayley had felt. With his chin bleeding and his mind racing, Kurt realized what Joe had discovered in the outback: a hovercraft was the ultimate all-terrain vehicle.

He raced on, desperately trying to think of a way to escape its grasp.

As kurt and Hayley raced off, Joe Zavala found himself pointed in the wrong direction, with the nose of his machine aimed toward the ridge that Kurt and Hayley had climbed. He got on the throttle fast and twisted the handgrips. The engine revved and the tracks spun, and Joe manhandled the nose of the snowmobile around to a new heading.

He shot forward, racing up a small hill and down the other side, almost T-boning one of the Russians.

Right behind the Russian sled, one of the gray hovercraft flew down the hill. The wide, flat hovercraft reminded Joe of a stingray. The central portion of the machine was raised to hold a crew cabin and a turbine engine, while the thinner surrounding section and the rubber skirt that drooped from it were there primarily to create the cushion of air that it rode on.

As the gray machine followed the Russian commandos, Joe cut in behind it. He had the impression its driver hadn’t seen him, since his attention remained locked on the original target. As they raced across the ice, Joe tried to get at the rifle strapped across his back, nearly wrecking in the process.

Eventually, he managed to slide the rifle around until it rested at his side. It was balanced by the strap that remained across his shoulder. Situated like this, he closed in on the target like a fighter pilot trying to save the life of his wingman. With the hovercraft crossing in front of him, Joe tried to flick off the safety, but the bulky gloves he wore made it impossible. He was still fumbling with it as the Russian snowmobile turned hard to the right.

The hovercraft followed, and Joe leaned into the turn, swinging wide, until he was back on target. He put the glove to his mouth, bit down on the fabric of the fingertips, and ripped the glove off. The frigid air chilled his fingers instantly, but with his bare hand he was able to grab the rifle grip, flip the safety off, and fire.

A spread of bullets lanced forth from the barrel to no effect.

The hovercraft turned left, and Joe fired again. This time, he hit the target — something confirmed by bits of fiberglass flying into the air — but still the hovercraft raced forward unaffected.

Ahead of them, the two Russian commandos had come to a narrow gap between a rocky ridge and a high drift of soft snow. They shot toward the gap, a fatal mistake.

The hovercraft’s driver lined them up easily and triggered his own weapon. A direct hit from the flash-draw stunned the men into unconsciousness and stalled the snowmobile’s engine. The fleeing sled turned sideways. Its right-hand ski caught a rut, and the machine tumbled out of control, ejecting the limp commandos in different directions.

Rather than repeat the snowmobile’s mistake, the hovercraft turned right. It raced up the hill, skidded sideways, and pointed its nose back around and down toward Joe.

Joe flipped the selector to full auto and fired at will, tearing up the front end of the hovercraft and shattering its windshield. Despite the damage, the charging machine didn’t stop.

Joe tried to dodge the oncoming craft, but he skidded on the ice. He was either about to get zapped or be decapitated. He dove off the snowmobile, throwing himself to the ground.

The hovercraft raced over the top of him, roaring like a tornado and hammering the snowmobile like a battering ram. The tremendous downward air pressure underneath the hovercraft’s skirt blasted Joe out to the side as if he were a newspaper caught in the swirling air behind a truck on the highway.

As soon as he tumbled to a stop, Joe was up and running. Across from him, the hovercraft began to turn back. It swung around and charged back toward him. Joe could just imagine the thugs inside, drooling as they growled: “Run him down!”

It wouldn’t take long.

As Joe lumbered through the snow, the hovercraft bore down on him at ten times his speed.

The whine of the approaching vehicle rose in Joe’s ears. He threw himself to the ground as the din of automatic gunfire rang out. He looked up just in time to see the hovercraft going off course and trailing smoke. It carried on for a hundred feet before losing power and crashing nose-first into the snow. It burrowed for ten feet before grinding to a halt.

Another snowmobile raced toward Joe and skidded to a stop.

“Get on!” Gregorovich yelled.

Joe normally preferred to drive, but he wasn’t about to argue. He clambered onto the seat, barely grabbing the handholds before Gregorovich gunned the throttle and took off.

A half mile away, Kurt was doing a yeoman’s job avoiding the stun blast of the flash-draw, but he could neither shake nor outrun their pursuer. He noticed only one advantage.

“We have better traction,” he yelled to Hayley.

“What?”

“That thing turns more like a boat or a plane, it skids and slides. But when we’re not on ice, we’re able to turn inside his radius every time.”

“How does that help us?”

“Watch,” he said, cutting hard to the right, racing back in the direction they’d just come.

The hovercraft dutifully followed, swinging wide, turning back on course, and then closing the gap again.