Watson pulled the suit up to his waist and cinched the ties that held it in place, then he turned to Emily to help her into her suit. He pulled it from her hands and held the back open as she stepped into the pants.

"Don't be scared," he said. "They'll never catch up to us."

She paused, stared at him, and said, "Aren't you scared?"

"Specking terrified," he admitted. He smiled at her as he pulled the armor up so that she could thrust her arms into the sleeves.

Once she had finished dressing, he finished as well. It was not an easy fit; he had to bend his legs and hunch his back to get the unitard over his shoulders. His ribs still hurt from the beating. The pain from his jaw, which still hung broken, now cut through the haze from his patches.

Before sealing himself in, Watson peeled the old patches from his neck and placed a single new one in their place. He'd have liked to use two or maybe three, for the long walk to the Air Force base; but this was his last.

The one-size-fits-all armor was a tight fit for Watson. It would not have fit Freeman, but he had his combat armor. He strapped a rifle on one shoulder and the oversized particle-beam cannon over the other. Crisscrossing bandoliers hung across his chest plate.

On the other side of the car, two of the bodyguards helped Howard Tasman dress. Once he was ready, one of them rolled the old man and his wheelchair out of the train while the other two stood outside and received him.

On a heart monitor on the back of Tasman's wheelchair, bars of light flashed, showing the rhythm and strength of his heart. Watson did not know if the old man had a weak heart, but Freeman clearly wanted to keep an eye on it.

Once Tasman and his guards were out of the way, Hughes came next, followed by his progeny.

The microphones inside their helmets might or might not have worked; but with Spaceport Security sludging, there would be no communications. Freeman pointed along the side of the tracks that led to the Air Force base, and the convoy started to move. First Tasman and his bodyguards began walking, following by the Hugheses.

With everyone wearing armor, Watson could not tell the Hugheses apart. He could not tell Emily from Gordon from the three sons. He wondered if that was how the clones felt, unable to tell one from another without memorizing fine details.

The bodyguards performed their job well. As long as Tasman's motorized wheelchair scooted him at a quick enough pace, they seemed to ignore him. When the wheels became bogged in sand or rubble, they picked him up and carried him like pallbearers hauling a casket.

Tasman, a cantankerous old fossil under the best of circumstances, waved his arms in the air every time the bodyguards touched his chair. At first Watson thought he was thanking them, then he realized the old bastard was pitching a fit.

Freeman grabbed Watson by the shoulder. As the others walked away, he handed Watson one of the M27s.

Watson took the gun and started to sling it over his shoulder, but Freeman stopped him. He held his own M27 by the forestock and trigger. Watson nodded and held his gun the same way.

Watson looked down the rails toward the Air Force base. He saw the people walking far ahead, shrinking into the distance. He looked back toward the spaceport, which had long ago vanished below the horizon.

How far have we gone? he asked himself. How far do we have to go?

During his briefing, he'd been told that the two facilities were ten miles apart. Maybe three miles left, he told himself. Maybe three miles. Three miles in low gravity on rough terrain in the wrong-sized space suit was a long walk.

How will they travel if they don't have the train? Watson asked himself. He hoped they had to travel by foot. Maybe those were the only choices on Mars, by train or by foot.

Holding his gun the way Freeman showed him, Watson started to leave, but Freeman stopped him again. He signaled for Watson to follow as he returned to the train. Without climbing back into the car, he reached into a doorway and pried open a crate that lay on the floor.

There was a control panel in the crate. Freeman flipped a switch on the panel, and a circle of red diodes blinked once in response. They blinked, then a second passed, and they blinked again.

Freeman closed the crate; and then he closed the train doors.

A bomb, Watson thought. Not a bomb...a trap. If they opened the train, they would set off the bomb; and, of course, they would open the train, they had no choice but to examine the train. Watson wondered how many of them the bomb would kill. He hoped Nailor was among them.

CHAPTER.

FIFTY-TWO.

About a half mile from the train, the bodyguards stopped while Tasman puttered on. They stood in a group, and others soon joined them. When Freeman and Watson reached the spot, they stopped as well.

This was the area where Cutter's fighter pilots had destroyed the rails. The ground where the tracks had been was burned black with yard-deep holes. Two of the three rails, sturdy metal pipe about two feet in diameter, had become an ambiguous wad that looked like melted candle wax.

As Watson walked along the third rail, he saw where it, too, had been destroyed, its melted remains lying in blackened soil. A new rail had been grafted over the expanse. Watson knelt and touched his gloved fingers into the soil. He reached forward and patted his hand against the ground. He stood and ran the same hand across one of the newly restored rails. So Cutter did destroy all of them, he thought.

Freeman stood over Watson, no doubt spotting the same things that he saw. He stuck his forefinger in the air and twirled it to catch people's attention, then he pointed ahead, signaling the convoy to move on.

Tasman was the first to move. The bodyguards followed, having to jog a few steps to catch the old man. The Hugheses followed. Watson and Freeman brought up the rear.

Soon after they passed the break in the rails, Mars Air Force base appeared in the distance. It stood out like a mountain range against the flat plains around it. The building was close enough that Watson could see details in its architecture.

The "soft-shelled" armor Watson wore weighed about thirty pounds on Earth. On Mars, with its weak gravity, the armor weighed less than ten pounds. Heavy enough. In the beginning, the walk felt like an adventure; but fighting the weight and stiffness of the armor, the convoy crossed less than three miles in the first hour.

Tasman's wheelchair, with its tiny wheels, moved easily across the terrain; but it teetered in slag and sank in sand. Some of the teens had held broad-jumping competitions in the beginning; but an hour into the hike, their energy had drained.

As long as the people kept ahead of him and did not stray from the tracks, Freeman ignored them. When a boy meandered away from the rails, Freeman picked the kid up and carried him back to the fold by his arm.

Since their radios did not work, the people found other forms of communication. As Freeman walked away, the kid spun around and flipped the bird.

Tasman and his bodyguards continued to lead the way.

Watson looked back along the track. Seeing a cloud of dust rising to the sky in the distance, he tapped Freeman on the shoulder and pointed back along the rail.

Freeman looked and nodded.

CHAPTER.

FIFTY-THREE.

They were less than a mile from the base when an explosion shook the ground and hurled bits of train in every direction. It was the flash that caught Watson's attention. He looked up in time to see a silvery shape tumbling through the air. He yelled, "Heads-up," but no one could hear him, so he ran ahead and tackled people to the ground.

Debris started to fall from the sky. Some people saw the bits of metal and plastic and just stood there. Tasman slithered out of his seat and curled into a ball on the ground. Age and disappointment had not dimmed the old man's will to survive.

A metal sheet fluttered like a butterfly with a ten-foot wingspan over their heads. Watson heard its warbling song through his hood. Shards of glass whistled past. Most of the dangers flew high overhead. Because of the limited Martian gravity and atmospheric resistance, they flew much farther than they would have on Earth.

Just as Watson determined that the "metal butterfly" must have been part of the roof of the train, a twenty-foot section bench dropped from the sky and stabbed upright into the dirt ahead.

Thank God for slow learners, Watson thought. Maybe it was Nailor, maybe it was Riley, or maybe it was just some of the foot soldiers; but Freeman had been able to trick one or more of them twice, once with a bomb in the train station and once with a bomb on the train. Natural selection, he thought. When they reached the base, he would congratulate Freeman for being an agent of Darwinism. Then he thought about Freeman and his cold glare and his humorless ways and changed his mind.

A minute passed, and nothing more fell out of the sky. The bodyguards stood, looked around to be sure they were safe, and loaded Tasman back into his wheelchair. The other people stood. Freeman walked to the front of the pack and directed them on.

Watson spotted something the others had missed. A person remained on the ground, a body lying facedown in the sandy soil. Watson could not tell if the person was breathing, not through the armor.

Praying that it was not Emily, he sprinted to the spot. He knelt beside the body and rolled it onto its back. Gordon Hughes stared up at him, his face the color of a ripe plum, his eyes bulging as if he'd been holding his breath. A layer of bile coated the inside of his glass faceplate.

Watson looked into the governor's visor and nearly vomited himself. He did not know what to do. He had no medical training. Even if he had, he could not open the sealed engineering armor without exposing Hughes to Mars's carbon-dioxide air.

He looked over his shoulder and saw that the others had not noticed, all but Freeman. In his dark green armor, he stood like a shadow. The angel of death, thought Watson. The harbinger.

Freeman approached slowly. Showing no interest in the body, he tapped a finger on Watson's visor then pointed back in the direction of the spaceport...of the nearing dust cloud.

Let the dead bury the dead, thought Watson.

The cloud of dust was much closer now. He guessed it was only half a mile behind them. The dust looked like a curtain skirting the desert floor.

Watson understood Freeman's message. The Spaceport Security clones had some kind of vehicle, and they were gaining ground. Freeman had reduced their numbers with his bomb, but the survivors were closing in.

Freeman unslung his sniper rifle.

Watson followed the angle of the rifle and looked back along the track. At first he saw nothing but tracks and desert, with a backdrop of dust and smoke and matte sky. Then some tiny black shapes along the bottom of the dust cloud came into view. At a distance, they looked like insects, but they were men on buggies-two-man, four-wheel carts formerly used by spaceport maintenance for servicing the train tracks and working around the landing zones.

Watson knew he could not run from this fight. He tightened his grip on his M27 and raised it; but Freeman laid his hand across the barrel and forced it down. He raised his rifle and aimed.

Heard through the hood of the armor, the rifle sounded distant, like Freeman had fired from a hundred feet away. Five hundred yards away, a six-wheeled buggy veered and swerved, then rolled upside down.

Freeman fired again. This time a buggy flipped onto its front end like a racehorse that has lost its front leg. As two Marines climbed out of the wreckage, Freeman shot them.

He fired again. A second passed, and he fired another shot. The first shot had hit the Marine driving the buggy. When the man beside him grabbed the wheel and righted the vehicle, Freeman shot him, too.

Watson wondered how many bullets the big man could carry. Did he have a hundred? Did he have a thousand? Spaceport Security had five thousand Marines.

But Freeman did not intend to kill every clone in Spaceport Security, just the ones on the buggies, the scouts. There were twelve vehicles. They were the advance guard, so to speak, the first ones on the scene.

They were only a couple of hundred yards out now. Freeman reloaded and fired.

Two of the drivers pulled their buggies nose to nose, forming a barricade. Four Marines in combat armor milled around the makeshift barricade. Watching them, Watson had the feeling that they thought they were safe behind their waist-high barrier.

Two of the Marines shot their M27s at Freeman and Watson. The guns were set to automatic fire. Bursts of gunfire echoed across the grounds. Watson had no idea where the bullets went. Except for the muzzle flashes and distant sounds, the gunfire could have been imaginary.

Freeman aimed at one of the Marines and fired. One of the men flew backward, tossing his M27 into the air.

Freeman picked off two of the three remaining Marines. The fourth cowered behind the buggies. He fired one quick burst from his M27, then he stood, tossed the weapon away, and raised his hands in the air.

Freeman pointed at the man with his rifle, then signaled Watson to go after him. He tapped Watson with the muzzle of his rifle, then swung the rifle in a long arc that ended in the direction of the buggies and the dead Marines.

"You have got to be kidding me," Watson shouted though he knew Freeman would not hear him. He shook his head in an exaggerated motion, making sure to turn the entire hood from one side to the other as he shouted, "No."

Freeman wrapped a hand the size of a small frying pan around the front of Watson's faceplate, and shoved him backward. Watson's feet came up from under him, and he landed on his ass.

As he stood, he saw Freeman walking toward that last Marine. He walked slowly and steadily, like a man fighting against a strong wind. Watson knew that Freeman did not intend to take the man to the base; he did not want prisoners.

He intended to kill the man, maybe with his hands to save a precious rifle round.

Watching Freeman walk toward that last Marine, Watson had to fight back the panic and revulsion. Freeman had wanted him to kill the man when he could have picked him off as easily as he shot the others. They might as well have been stationary targets on a shooting range.

Why did he want me to bother killing this one, when there are more on the way? Watson asked himself. There will be plenty to kill.

"Plenty to kill," he repeated the words out loud. "Batting practice."

Like a father teaching his son how to swing a bat before a real game, Watson thought. I have to learn to kill. Freeman wasn't trying to teach him how to fire a gun, he was trying to acclimate him to the feel of murder. Eliminate the moral dilemmas now, then I can shoot without worrying about my conscience later.

Thirty feet ahead of him, Freeman approached that final Marine. Watson followed, walking at first, then sprinting. Freeman glanced back and waited for him.

They stood together in silence, almost as if Freeman could read the resolve in Watson's posture. Watson stalked past Freeman.

You wanted to kill me. You came here to kill me. If I surrendered, you would have killed me. You would kill me. You would kill Emily. Harris would have killed you, Watson told himself.

He tried to ignore a louder voice in his head screaming, I don't want to do this. He's alive. He's a man, a human.

The Marine stood with his hands in the air.

He's not a man; he's an insect, Watson told himself. The combat armor was hard and dark, like the shell of a beetle. It had no face, just a shiny glass plate.

Not a man, a bug. He would kill me. He came to kill me. More are coming.

The man was nameless and faceless.

I don't want to do this. I don't want to do this!

Eight yards away. Watson imagined it was Franklin Nailor hidden inside the armor and fired his M27.