He stopped the car and jumped out, to look into the sky and see the source of the sound. Planes, wave upon wave of them, coming in and down on Center from the southwest-from toward the Gulf of California. They were coming as fast as their jets could send them; almost as fast as the sound that preceded them. The first wave parted in definite formations as it came in, part of it dissolving to strike at the six antiaircraft gun positions that surrounded Center and the main body coming in on Center, itself.

"What is it?" June was beside him with her hand on his arm. "They couldn't be ours- ".

"No," he said tonelessly, "they're not ours."

They stood and watched-there was nothing else they could do. The first wave pa.s.sed low above them with a deafening, ground-shaking roar and was gone in the s.p.a.ce of two breaths. The bombs shot downward in fast, flat arcs and their explosions raced through the city at the speed of the planes that had dropped them; red and yellow spurts of flame that leaped upward and hurled strange, broken things into the air, to be silhouetted momentarily against the pale dawn.

The second wave came close behind the first; a roar that swelled into a crescendo then boomed into the distance with the bomb bursts a thunderous staccato racing along on the ground behind them. Then the antiaircraft guns came to life, licking thin, defiant tongues of flame at the invaders. The third wave concentrated on the gun positions and some of them plunged to earth, trailing black plumes of smoke, but three of the guns were still when the others had pa.s.sed on.

For a few seconds Center was almost quiet by contrast to the thunder and fury that had filled it and a dog could be heard somewhere among the wreckage, barking and whining anxiously as it ran back and forth in a vain search for its master. A woman screamed, a sound that cut through the morning air like a thin, sharp knife, then the alarm siren began to moan and wail, half drowning the sound of cold motors breaking into life and the shouted orders of men.

The next attack on Center was a wave of fighters, boring in on the machine-gun towers in the Computer and laboratory area. The machine guns in the towers met their fire and tracer bullets were golden lances that met and crossed and struck the towers, to ricochet away in beautiful parabolic curves. Two of the attacking planes wavered and spun to the ground, but when the others turned to renew the attack there were no guns left to oppose them.

They began to strafe the streets and the cars that were trying to make their way through the debris, patrolling the area around Lab 4 and concentrating vicious fire on any vehicle that attempted to go in that direction. They had not bombed the laboratory area or the adjacent landing strip, and Knight realized, as he watched them, that there could be but one reason.

Russo-Asia had planned for this day for a long time. They had planned well; so well that even America's own Intelligence agents had thought the talks of peace were sincere.

They had stressed the desirability of friendship between East and West and the West had hoped, and half-believed, and let themselves be caught unawares and unprepared. The anonymous phone call implicating Connie had been only a touch to add weight to the evidence against Miles; the evidence that had resulted in the postponement of the ship's flight and had insured that neither Miles nor anyone else would be inside the ship and in position to prevent its seizure when the attack came.

It had all been done with exact and detailed precision; the timing of the robot's phone call to Security, the attack in the early dawn before Clarke or Vickson had time to appear-or was Vickson their agent, and already inside the ship?

He would have to move fast-if it wasn't already too late.

He swung the door wide and thrust June into the car. "Get behind that wheel and drive like h.e.l.l back to where Connie is. If a plane comes at you, jump and run-don't stay in the car or they'll get you. I'll have to try to get to the ship-"

A plane roared over them and its tracers made a bright splash of yellow phosph.o.r.escence on the pavement beside them. The tires of an army truck screamed at the intersection a hundred feet behind them and June, watching, cried, "Connie!"

Connie was coming toward them across the intersection, trying to run as best she could, and the army truck was braking and slewing desperately to avoid hitting her. Then the plane banked and turned and came roaring back at them and June half sobbed a terrified "No!" as its tracers licked down at the truck and across it, to lash at Connie who had reached the curb. She crumpled to the walk and the plane went its way, while the army truck wandered aimlessly down the street with the dead driver slumped over the wheel.

"No!" June shoved past him, her face white with fear, and ran to her sister. He followed, sick at heart with the foreknowledge of what he would see.

Connie was lying very still, her face like that of a pale, waxen doll that had gone to sleep. June was kneeling beside her, holding her hand and saying over and over in a dazed voice: "Connie . . . Connie . . . why did you do it?"

"She had to," he said softly. "She was going to you because you might need her. She was a nurse and she was going to you and Tim and all those who might be hurt and in need of her."

The siren whimpered off into silence and the bark of one lone antiaircraft gun came to them, to falter and stop as another attack of bombers roared over it.

"They killed her!" June's voice was numb with the shock. She held Connie's hand between both her own, a bright red splotch on her knee where it touched Connie's side as she knelt beside her. "They killed her-they killed my sister!"

She raised her face to look at the planes circling above them and a terrible, savage hatred blazed through the hurt and pain in her eyes.

Then the tears, that the first shock had held back, came and he hurried quietly away, leaving her crying with shaking, m.u.f.fled sobs beside her sister. There was nothing he could do to comfort her and it would be better for her to not follow him.

He ran in a steady trot, two blocks to the highway that paralleled the western boundary of the laboratory area, then down along it. Trees had been transplanted beside the highway in years past and he kept under the shelter of their concealment as he ran. He stopped once, to dart out on the pavement where a jeep lay overturned and riddled with machine-gun bullets. A soldier was sprawled lifelessly beside it, his heavy automatic rifle still in his hands. Knight seized the rifle and the belt of cartridge clips and ran back to the shelter of the trees as a plane spotted him. Its bullets cut twigs from the limbs above him and made a thunk-thunk sound as they buried themselves in the trunk of the tree. Then the plane was gone and he ran on toward the western entrance that was the closest to Lab 4.

The fighter planes widened in their circling to leave a clear s.p.a.ce above the laboratory area as he reached the gate, then the troop-transport planes came in-six of them. The sky blossomed with chutes, the Russo-Asian paratroopers firing even as they descended. Other rifles were firing from within Center and from the area outside the main gate, and occasionally a paratrooper would jerk, then dangle limply in his harness as he drifted downward.

The last group of planes came in; a light, fast bomber surrounded by a protecting ring of fighters. The objective of the light bomber, he saw, was the landing strip nearest to Lab 4.

The bomber's mission would not be to bomb the landing strip, and there could be no doubt as to the ident.i.ty of the pa.s.senger it carried. It slowed and dropped to make its landing and he began to run toward the ground-control station and Lab 4 that set two hundred feet beyond it.

He was protected from the fighter planes by their own paratroopers and the aim of the paratroopers, shooting from their swinging suspension, was uncertain as they tried to catch his running, weaving figure in their sights. Bullets kicked up puffs of dust beside and behind him but none touched him. He had reached the ground-control station when the first paratrooper reached the ground. The vicious rip of a burst of well-aimed bullets slammed against the steel corner of the building a split-second after he had rounded it.

Two more paratroopers landed even as he ran for the door of the station, adding their fire to their comrade's. It was two hundred feet to the ship and, now that they were on the ground, the aim of the paratroopers would be deadly and certain. He would never live to run a tenth of the distance to the ship. And the others were landing, by three's and four's.

But it didn't matter-he would be in supreme control of the ship from the auxiliary station.

The guards were lying before the door of the station, dead, and the door was ajar.

Simultaneously, he saw the other thing that was happening; the roof of Lab 4 was sliding back and the walls were dropping into the ground. He leaped through the doorway and to one side as paratrooper bullets hammered at him, the automatic rifle held ready before him.

The room was deserted but for the robot, George. George turned away quickly from the control panel at the far end of the room, and Knight saw the switch was on that lowered the walls of Lab 4.

"Turn that switch off!" he commanded. "Raise those walls again."

The robot stepped toward him with long, swift strides, seeming not to hear him. The metal arms were half outstretched before it and a sudden, icy premonition ran a cold finger up his spine.

"Stop!"

It came on without slackening its speed, the dark eyes thoughtful and the steel hands reaching out toward him-hands that had the strength to tear his head from his body. "Stop!"

The steel hands swooped toward his throat and he leaped to one side. It spun with him, as quick as he for all its ponderous bulk, and then it sprang like a great cat.

There was no time to wonder why the robot wanted to kill him, no time to dodge. The rifle was still leveled before him and he pressed the trigger. The great ma.s.s of the robot lurched and shuddered as twenty bullets, each with a muzzle energy of three thousand foot pounds, tore through its body within a s.p.a.ce of two seconds. It reeled and crashed to the floor, to lay inert while the dark eyes stared up at him with their same expression of thoughtful, patient waiting.

But it was dead. Its brain was a riddled wreckage and it was as dead as ever a robot could be.

He ran to the control board and slapped the switch that would re-erect the walls and roof of Lab 4, wondering why the robot had tried to kill him. A machine has no volition, yet it had walked toward him with the deliberate intent to kill him, heedless of his command for it to stop. It might as well have been deaf- Of course! It had been deaf! It had been sent recently from Lab 4 with orders to lower Lab 4 into the ground and to kill anyone who entered the ground-control station. Then, after the orders were given, the microphones that were its ears had been disconnected and it had gone on its mission, stone-deaf and unable to hear any orders that would countermand the ones given it.

He hurried back to the door, slipping a fresh clip of cartridges into the rifle as he went. He opened it a quick, cautious ten inches and saw that the paratroopers were taking up positions in a wide circle around the ship. Two of them saw the partial opening of the door and he had time only for one quick glance before their bullets pounded against it as he slammed it shut.

He had had time to see the ship, standing bright and naked in the first rays of the sun.

The walls that had enclosed it had disappeared. The air lock of the ship had been open and a man had been standing there, the rising sun red on his face-Vickson. He had been looking toward the landing strip and a car racing toward the ship-a car whose dust trail led back to the light bomber.

He locked the door to prevent anyone entering the station, while the bullets hammering methodically against the outside of it informed him that they were seeing to it that no one left it. He went back to the control board and looked at the switch that he had closed before going to the door; the switch that should have re-erected Lab 4 around the ship. It had not, and he saw the reason why; George had ripped out the wires behind the panel that led to the switch. They were lying tangled on the floor behind the panel and he could never, in the short time he had, reconnect them.

He seated himself in the chair before the control board and turned on the observer's viewscreen. His own viewscreen came to life, showing the interior of the ship's control room. It was still empty.

He closed the switch that would give his own commands precedence over any given inside the ship and said: "Ship's drive control-disregard all orders given you by anyone in the ship's control room. Disregard all impulses from the pilot's control panel."

Only silence answered him and he said sharply, with sudden anxiety, "Ship's drive control-acknowledge that order!"

Silence.

He tried again, coldly, unpleasantly certain that it would be in vain. "Ship's drive control-acknowledge!"

Again the dead silence was his answer and he knew there was no use to try any more.

The units that permitted the ground-control station to control the ship had been sabotaged and he was helpless to prevent the ship's take-off. Bullets continued to rattle against the door, warning him how fatal would be any attempt to leave the station. He was helpless so long as he remained in the station; he would be both helpless and dead a split-second after he opened the door to leave the station. Yet, he had to do something.

He estimated the time that had gone by since he had seen the car speeding from the bomber to the ship. It would have been Cullin, of course; it would be Cullin and Vickson who took the ship into the sky, with Vickson at the pilot's seat and Cullin behind him, watching him. Vickson knew as well as Miles how to operate the manual drive controls, and there was no hope that he would make a mistake and wreck the ship in a take-off.

Even Cullin, alone, could lift the ship by simple voice command to the drive control. The Center forces would be closing in on the ship as the fighter planes exhausted the ammunition they were forced to use so continually, but they would be too late.

A sound broke the silence of the observer's viewscreen, the sound of someone entering the control room. It was Cullin, wearing the black and gray uniform of a high official of the State Police, and he was alone. He took one quick look at the room, then walked straight to the observer's chair in the manner of a man who knew exactly what he was going to do.

At the sight of Knight's face in the observer's viewscreen he smiled in sudden, pleased surprise. Knight spoke the same greeting he had spoken at Punta Azul: "Going somewhere, Cullin?"

Cullin seated himself in the observer's chair, still smiling and taking his time about answering. "Why, yes," he said, "I am going somewhere. Vickson was telling me you were in there, but I was afraid you had been rendered permanently speechless by your faithful George." Cullin shifted his eyes to look past Knight at the robot lying on the floor across the room. "I see you had sufficient intelligence to destroy the robot before it destroyed you. It was very useful to me-via Vickson's orders to it-but it's just as well that it failed to carry out its last order; to throttle anyone who entered the station. You and I can now chat pleasantly about cabbages and kings and sealing wax and a man named Cullin who is, as you feared, going somewhere."

"Alone?" Knight asked. "Where's Vickson?"

"Outside. He was rather surprised that he couldn't go with me."

"He is a pilot as well as observer-why don't you take him along?"

"You builders of this ship thoughtfully gave it a robotic brain for the drive that makes the pilot's manual controls unnecessary. Whoever controls this ship can write his own ticket, so I'll take it up alone and there'll be no danger of a doublecross, no doubt as to who will write the ticket."

Cullin reached out and turned the red k.n.o.b to the right. "No pilot is needed," he said. "You've made the ship foolproof."

"How did you manage to keep Vickson from taking the ship up before you ever got to it?"

"He was selected, Knight, years ago. For all his pa.s.sing of the tests for superior mental stability, Vickson is a man who places a very high value on his own life. Of all the men who had full access to the ship, Vickson was the best suited to our purpose. There are various ways of persuading various types of men and compelling them to co-operate.

With Vickson it was very easy and simple-we used the y drug.

"Perhaps you've heard rumors of it. Our own scientists whipped it up for us several years ago, and it's very efficient. Thirty days after the administration of the drug the subject is stricken with intense pain. This pain increases by the hour and only the antidote, made from a batch of the original drug, can stop the increasing pain and eventual death. We have occasionally let Vickson wait a few hours extra just to keep him convinced of the desirability of wholehearted co-operation with us. Had he been foolish enough to take the ship he would have died in a great deal of agony within six hours, since everything was timed very carefully, including the last administration of the y drug."

"And what becomes of Vickson now?"

"I wouldn't know." Cullin shrugged his shoulders with disinterest. "He's served his purpose for me-I have no further use for him."

"And no antidote for him?"

"I rather doubt that the good citizens of what is left of Center will permit him to suffer very long."

No, thought Knight, they won't, but it was Cullin who had planned it, coldly, deliberately- "I've planned this for a long time," Cullin said, as though he had been reading Knight's mind. "All my life I've played second-fiddle to someone else. Now, the world will dance to my tune."

Knight looked at him sharply and Cullin laughed with genuine mirth. "No, I'm not insane. This ship is my whip; I'll use the threat of it to whip the world into billions of gentle, obedient horses."

"Obedience seems to be a mania with you."

"It produces the desired results. That's why I liked your robot; no threats were necessary, no y drugs. It accepted orders without question and carried them out without question."

The bullets were no longer banging against the door, Knight noticed. That would mean that the Center forces had gathered in strength and had drawn in closer; that the paratroopers had no time to spare for watching the door. Cullin liked the unquestioning obedience of a robot and he, Knight, could not keep him from giving the order to the drive control that would lift the ship. The robotic brain that was the drive control would obey instantly and without question, but if Cullin should not word his command in the proper manner- "Once more I'm leaving you. Listen while I give the order to your own ship." Cullin smiled once more, triumphant and exultant, and gave the order: "Ship's drive control-accelerate!"

It was the command Knight had hoped he would give. It was a command the robotic brain would obey instantly and Cullin could never countermand.

It required slightly less than three seconds for the primary activation of the ship's drive, then the thrust of acceleration came and the ship hurled itself upward. Cullin was shoved deep into the cushioned seat by it, pinned and chained by it. He tried vainly to speak, the horror of sudden realization and fear in his eyes, then the blankness of unconsciousness clouded them. Knight turned away from the viewscreen. Cullin would be conscious when he returned to it later in the day. Cullin would not die for a long, long time-the doctor in the control room was very competent.

He went to the door and stepped outside. The ship was gone, already beyond sight, and the last of the paratroopers were throwing down their guns and surrendering to the Center forces that surrounded them. The planes were gone; back to carriers somewhere in the Pacific, he presumed, there to depend upon the threat of the disintegrator rays to shield them and the carriers from retaliation.

But there would be no war. Russo-Asia had put all her eggs in one basket and one wrong word had sent that basket away forever.

Someone was lying near Lab 4; motionless on the ground, his rimless gla.s.ses knocked askew by the bullet that had killed him and looking mild and apologetic, even in death. Knight felt a sense of relief. Vickson had paid the penalty and it had been gentle compared with the penalty Cullin would pay. It was as it should be.

"Blacky."

June was coming toward him, a cartridge belt sagging from her waist and a rifle in her hands.

"We've lost, haven't we?" she asked, stopping before him. "They took the ship and we couldn't stop them."

"The ship will never come back," he said. He looked down at her, her grimy hands clutching the rifle, her clothes torn and her face scratched and dirty and tear-streaked. He saw that most of the clips were gone from the cartridge belt.

"They got Tim," she said. "They must have killed him in the first bombing. I ought to go back and try to help-there are so many people in need of help and it's what Connie would want me to do. But first"-she looked up at him, tears suddenly threatening to wash a new channel through the dirt on her face-"can't we take her-home?"

He took the rifle she still held and let his hand rest on her shoulder.

"First, we'll take Connie home."

5.

The doctor's pre-flight training had included the order to keep the pilot informed of each man's physical condition.

How long had it been since the doctor last changed the words on the pilot's communications panel? Was his time finally within short minutes of its end? It was no longer hours, but minutes. The words read: OBSERVER HAS A LIFE EXPECTANCY OF ONE HOUR AT PRESENT ACCELERATION. DEATH FOR OBSERVER WILL.

RESULT UNLESS ACCELERATION IS REDUCED WITHIN THAT PERIOD.

How many days and weeks had gone by since he had first given the fatal command to the drive control? It had been Vickson who had done the thing that would so soon culminate in his death. Vickson, the mild and apologetic. Vickson had feared that he would be deemed dispensable, and this had been his means of revenge. Vickson had told him how to word the command to the drive control: "Ship's drive control-accelerate!"

Vickson had known that the robotic drive control would continue to accelerate until full acceleration was reached. Vickson had known full acceleration would be maintained until he ordered it reduced. Vickson had known that the first surge of acceleration would render him speechless and unconscious. Vickson had known that the robot doctor in the control room would do the only thing possible to save his life while under full acceleration: by-pa.s.s his heart with a mechanical heart, and put it in conjunction with a mechanical lung that frothed and aerated his blood. Vickson had known he would live a long time that way, with the doctor watching over him and administering nutrients into his bloodstream. Nutrients-and the antihysteria drug that had been designed to keep the observer's mind clear and logical so that he could meet any emergency!