"We can't stop!"

"What?"

Michael cupped his mouth. "We have to keep moving!"

The train had slowed to a crawl. Peter saw Caleb and Hollis lifting a woman into one of the three open boxcars trailing the engine; Michael was helping to pull Mausami up the ladder into the cab, Amy pushing from behind. Peter began to run with his brother, trying to match their speed with the ladder; as Amy ducked into the hatch, Theo grabbed hold and began to ascend. When he reached the top, Peter dove for the ladder and pulled himself up, his feet swinging free. Behind him he heard a sound of gunfire, shots pinging off the sides of the cars.

He slammed the door closed behind him to find himself in a cramped compartment, glowing with a hundred tiny lights. Michael was sitting at the control panel, Billie beside him. Amy had withdrawn to the floor behind Michael's chair, her eyes wide, her knees protectively pulled to her chest. To Peter's left, a narrow hallway led aft.

"Flyers, Peter," Michael said, swiveling in his chair. "Where the hell did Theo come from?"

Peter's brother was slumped on the floor of the hallway; Mausami was holding his head against her chest, her bloody leg folded under her.

Peter directed his voice to the front of the cab. "Is there a med kit in this thing?"

Billie passed him a metal box. Peter popped it open and withdrew a cloth bandage, rolling it into a compress. He tore the fabric of Mausami's pant leg away to reveal the wound, a crater of torn skin and bloody flesh, and placed the bandage against it and told her to hold it there.

Theo lifted his face, his eyes flickering. "Am I dreaming you?"

Peter shook his head.

"Who is she? The girl. I thought ... " His voice trailed away.

For the first time it struck him: he had done it. Take care of your brother.

"There'll be time later, okay?"

Theo managed a weak smile. "Whatever you say."

Peter moved to the front of the cab, between the two seats. Through the slit of windshield between the plates he could see a view of desert in the beam of the headlamp and the tracks rolling under them.

"Is Babcock dead?" Billie asked.

He shook his head.

"You didn't kill him?"

The sight of the woman filled him with a sudden anger. "Where the hell was Olson?"

Before she could answer, Michael broke in. "Wait, where are the others? Where's Sara?"

The last Peter had seen her, she was with Alicia at the gate. "I think she must be in one of the other cars."

Billie had opened the cabin door again, leaning out; she ducked her head back inside. "I hope everybody's on board," she said, "because here they come. Hit the gas, Michael."

"My sister could still be out there!" Michael shouted. "You said no one gets left!"

Billie didn't wait. She reached across Michael, knocking him back into his chair, and gripped a lever on the panel, pushing it forward. Peter felt the train accelerate. A digital readout on the panel sprang to life, the number swiftly rising: 30, 35, 40. Then she shoved her way past Peter into the hallway, where a ladder in the wall led to a second hatch in the ceiling. She briskly ascended, turning the wheel, directing her voice to the rear of the train. "Gus! Up top, let's go!"

Gus jogged forward, dragging a canvas duffel bag, which he unzipped to reveal a pile of short-barreled shotguns. He passed one to Billie and took one for himself, then lifted his grease-stained face to Peter, handing him a weapon.

"If you're coming," he said gruffly, "you might want to remember to keep your head down."

They ascended the ladder, Billie first, then Gus. As Peter lifted his head through the hatch, a blast of wind smacked him in the face, making him duck. He swallowed, pushing his fear down inside himself, and made a second attempt, easing through the opening with his face turned toward the front of the train, sliding onto the roof on his belly. Michael passed him the shotgun from below. He eased into a crouch, trying to find his footing while simultaneously cradling the shotgun. The wind was slapping him, a continuous pressure threatening to push him over. The roof of the engine was arched, with a flat strip down the middle. He was facing the rear of the train now, giving his weight to the wind; Billie and Gus were already well ahead of him. As Peter watched, they leapt the gap between the first and second boxcars, making their way aft, into the roaring dark.

He first saw the virals as a region of pulsing green light from the rear. Above the din of the engine and the squeal of the wheels on the rails he heard Billie yelling something, but her words were yanked away. He drew a breath and held it and leapt the gap to the first boxcar. Part of him was wondering, What am I doing here, what am I doing on the roof of a moving train, while another part accepted this fact, strange as it seemed, as an inevitable consequence of the night's events. The green glow was closer now, breaking apart as it widened into a wedge-shaped mass of bounding points, and Peter understood what he was seeing-that it was not just ten or twenty virals but an army of hundreds.

The Many.

The Many of Babcock.

As the first one took shape, vaulting through the air toward the rear of the train, Billie and Gus fired. Peter was halfway down the first boxcar now. The train shuddered and he felt his feet begin to slide, and just like that the shotgun was gone, falling away. He heard a scream and when he looked up there was no one-the place where Billie and Gus had stood was empty.

He had barely found his footing again when a huge crash from the front of the train pitched him forward. The horizon collapsed; the sky was gone. He was sliding on his belly down the sloping roof of the car. Just when it seemed he would sail into space, his hands found a narrow lip of metal at the top of one of the armored plates. There was no time even to be afraid. In the whirling darkness he sensed the presence of a wall shooting past him. They were in some kind of tunnel, boring through the mountain. He held on fast, feet swinging, scrabbling at the side of the train, and then he felt the air opening beneath him as the door of the boxcar flew open, and hands grabbing him, pulling him down and in.

The hands belonged to Caleb and Hollis. In a heap of arms and legs they spilled onto the floor of the boxcar. The interior was lit by a single lantern, swaying from a hook. The car was nearly empty-just a few dark figures huddled against the walls, apparently immobilized by fear. Beyond the open door the walls of a tunnel were flying past, filling the space with sound and wind. As Peter climbed to his feet, a familiar figure emerged from the shadows: Olson Hand.

A furious anger broke inside him. Peter seized the man by the scruff of his jumpsuit, shoving him against the wall of the boxcar and pushing his forearm up against his throat.

"Where the hell were you? You left us there!"

All color was drained from Olson's face. "I'm sorry. It was the only way."

All at once he understood. Olson had sent them into the ring as bait.

"You knew who it was, didn't you? You knew it was my brother all along."

Olson swallowed, the point of his Adam's apple bobbing against Peter's forearm. "Yes. Jude believed others would come. That's why we were waiting for you in Las Vegas."

Another crash detonated from the front of the train; everyone went spilling forward. Olson was ripped from Peter's grasp. They were out of the tunnel again, back on open ground. Peter heard gunfire from outside and looked to see the Humvee racing past, Sara in the driver's seat, her knuckles clenched to the wheel, Alicia up top on the big gun, firing in concentrated bursts toward the rear of the train.

"Get out!" Alicia was waving frantically toward the last boxcar. "They're right behind you!"

Suddenly all the people in the car were yelling, shoving, trying to scramble away from the open door. Olson gripped one of the figures by the arm and pushed her forward. Mira.

"Take her!" he yelled. "Get her to the engine. Even if the cars are overrun, it's safe there."

Sara had drawn alongside, matching her speed to the train's, trying to narrow the space.

Alicia was waving to them: "Jump!"

Peter leaned out the door. "Bring it closer!"

Sara drew in. The racing vehicles were less than two meters apart now, the Humvee positioned below them on the angled rail bed.

"Reach out!" Alicia called to Mira. "I'll catch you!"

The girl, standing at the edge of the doorway, was rigid with fear. "I can't!" she wailed.

Another splintering crash; Peter realized the train was barreling through debris on the tracks. The Humvee swayed away as something large and metal went whirling through the space between the vehicles, just as one of the huddled figures leapt to his feet and made a dash for the door. Before Peter could speak, the man had hurled himself into the widening breach, a desperate plunge. His body slammed into the side of the Humvee, his outstretched hands clawing at the roof; for a moment it seemed possible that he would manage to hold on. But then one of his feet touched the ground, dragging in the dust, and with a wordless cry he was whisked away.

"Hold it steady!" Peter yelled.

Twice more the Humvee approached. Each time, Mira refused to go.

"This won't work," Peter said. "We'll have to go over the roof." He turned to Hollis. "You go first. Olson and I can push you up."

"I'm too heavy. Hightop should go, then you. I'll lift Mira up."

Hollis dropped to a crouch; Caleb climbed aboard his shoulders. The Humvee had swayed away again, Alicia firing in short bursts at the rear of the train. With Hightop on his shoulders, Hollis positioned himself at the edge of the door.

"Okay! Let go!"

Hollis ducked away, keeping one hand gripped on Caleb's foot; Peter grabbed the other. Together they pushed the boy upward, propelling Caleb over the lip of the door.

Peter ascended the same way. From the roof of the car he could see that the mass of virals, having passed through the tunnel, had broken apart into three groups-one directly behind them, two following on either side. They were racing in a kind of gallop, using both their hands and their feet to propel themselves forward in long leaps. Alicia was shooting at the head of the central group, which had closed to within ten meters. Some went down, dead or injured or merely stunned he couldn't tell; the pod closed over them and kept coming. Behind them the other two groups began to merge, passing through one another like currents of water, separating once again to re-form their original shapes.

He lay on his belly beside Caleb and reached down as Hollis lifted Mira up; they found the frightened girl's hands and pulled, drawing her onto the roof.

Alicia, below them: "Get down!"

Three virals were on the roof of the last boxcar now. A blast of fire erupted from the Humvee and they jumped away. Caleb was already vaulting across the gap to the engine. Peter reached for Mira but the girl was frozen in place, her body pressed to the roof of the car, her arms hugging it as if it were the one thing that might save her.

"Mira," Peter said, trying to pull her free, "please."

Still she held on. "I can't, I can't, I can't."

From below, a clawed hand reached up, wrapping around her ankle. "Poppa!"

Then she was gone.

There was nothing else he could do. Peter dashed toward the gap, took it at a leap, and dropped through the hatch behind Caleb. He told Michael to hold the train steady and swung open the door to the cabin and looked aft.

The virals were all over the third boxcar now, clinging to the sides like a swarm of insects. So intense was their frenzy that they appeared to be fighting with one another, snapping and snarling for the right to be the first ones inside. Even over the wind, Peter could hear the screams of the terrified souls inside.

Where was the Humvee?

Then he saw it, racing toward them at an angle, bouncing wildly over the hardpan. Hollis and Olson were clinging to the vehicle's roof. The big gun was depleted, all its ammo spent. The virals would be all over them any second.

Peter leaned out the door. "Bring it closer!"

Sara gunned the engine, drawing alongside. Hollis was the first to grab the ladder, then Olson. Peter pulled them through into the cab and called down, "Alicia, you go!"

"What about Sara?"

The Humvee was drifting away again, Sara fighting to keep them close without colliding. Peter heard a crash as the door of the last boxcar was ripped away, tumbling end over end into the receding darkness.

"I'll get her! Just grab the ladder!"

Alicia jumped from the roof of the Humvee, hurling her body across the gap. But the distance was suddenly too great; in his mind Peter saw her falling, her hands grabbing at nothing, her body tumbling into the crushing rush of space between the vehicles. But then she had done it; her hands had found the ladder, Alicia was climbing hand over hand up the train. When her feet reached the bottom rung, she turned, stretching her body into the gap.

Sara was gripping the wheel with one hand; with the other she was frantically trying to wedge a rifle into place to brace the gas pedal.

"It won't stay!"

"Forget it, I'll grab you!" Alicia called. "Just open the door and take my hand!"

"It won't work!"

Suddenly Sara gunned the motor. The Humvee shot forward, pulling ahead of the train. Sara was on the edge of the tracks now. The driver's door swung open. Then she hit the brakes.

The edge of the train's plow caught the door and sheared it off like a blade, sending it whirling away. For a breathtaking instant the Humvee rocked onto its two right wheels, skidding down the embankment, but then the left side of the vehicle banged down. Sara was moving away now, rocketing across the hardpan at a forty-five-degree angle to the train; Peter saw a skid in the dust and then she was pulling alongside again. Alicia stretched a hand out into the gap.