"Come along," he said needlessly to the Fury. "Hurry!" It came, matching its speed to his, the enigmatic timer inside it ticking the moments away toward that instant when the two-handed engine would smite once, and smite no more.

Hartz sat in the Controller's office behind a brand-new desk, looking down from the very top of the pyramid now over the banks of computers that kept society running and cracked the whip over mankind. He sighed with deep content.

The only thing was, he found himself thinking a good deal about Danner. Dreaming of him, even. Not with guilt, because guilt implies conscience, and the long schooling in anarchic individualism was still deep in the roots of every man's mind. But with uneasiness, perhaps.

Thinking of Danner, he leaned back and unlocked a small drawer which he had transferred from his old desk to the new. He slid his hand in and let his fingers touch the controls lightly, idly. Quite idly.

Two movements, and he could save Danner's life. For, of course, he had lied to Danner straight through. He could control the Furies very easily. He could save Danner, but he had never intended to. There was no need. And the thing was dangerous. You tamper once with a mechanism as complex as that which controlled society, and there would be no telling where the maladjustment might end. Chain-reaction, maybe, throwing the whole organization out of kilter. No:

He might someday have to use the device in the drawer. He hoped not. He pushed the drawer shut quickly, and heard the soft click of the lock.

He was Controller now. Guardian, in a sense, of the machines which were faithful in a way no man could ever be. Quis custodiet, Hartz thought. The old problem. And the answer was: Nobody. Nobody, today. He himself had no superiors and his power was absolute. Because of this little mechanism in the drawer, nobody controlled the Controller. Not an internal conscience, and not an external one. Nothing could touch him…

Hearing the footsteps on the stairs, he thought for a moment he must be dreaming. He had sometimes dreamed that he was Danner, with those relentless footfalls thudding after him. But he was awake now.

It was strange that he caught the almost subsonic beat of the approaching metal feet before he heard the storming steps of Danner rushing up his private stairs. The whole thing happened so fast that time seemed to have no connection with it. First he heard the heavy, subsonic beat, then the sudden tumult of shouts and banging doors downstairs, and then last of all the thump, thump of Danner charging up the stairs, his steps so perfectly matched by the heavier thud of the robot's that the metal trampling drowned out the tramp of flesh and bone and leather.

Then Danner flung the door open with a crash, and the shouts and tramplings from below funneled upward into the quiet office like a cyclone rushing toward the hearer. But a cyclone in a nightmare, because it would never get any nearer. Time had stopped.

Time had stopped with Danner in the doorway, his face convulsed, both hands holding the revolver because he shook so badly he could not brace it with one.

Hartz acted without any more thought than a robot. He had dreamed of this moment too often, in one form or another. If he could have tampered with the Fury to the extent of hurrying Danner's death, he would have done it. But he didn't know how. He could only wait it out, as anxiously as Danner himself, hoping against hope that the blow would fall and the executioner strike before Danner guessed the truth. Or gave up hope.

So Hartz was ready when trouble came. He found his own gun in his hand without the least recollection of having opened the drawer. The trouble was that time had stopped. He knew, in the back of his mind, that the Fury must stop Danner from injuring anybody. But Danner stood in the doorway alone, the revolver in both shaking hands. And farther back, behind the knowledge of the Fury's duty, Hartz's mind held the knowledge that the machines could be stopped. The Furies could fail. He dared not trust his life to their incorruptibility, because he himself was the source of a corruption that could stop them in their tracks.

The gun was in his hand without his knowledge. The trigger pressed his finger and the revolver kicked back against his palm, and the spurt of the explosion made the air hiss between him and Danner.

He heard his bullet clang on metal.

Time started again, running double-pace to catch up. The Fury had been no more than a single pace behind Danner after all, because its steel arm encircled him and its steel hand was deflecting Danner's gun. Danner had fired, yes, but not soon enough. Not before the Fury reached him. Hartz's bullet struck first.

It struck Danner in the chest, exploding through him, and rang upon the steel chest of the Fury behind him. Danner's face smoothed out into a blankness as complete as the blankness of the mask above his head. He slumped backward, not falling because of the robot's embrace, but slowly slipping to the floor between the Fury's arm and its impervious metal body. His revolver thumped softly to the carpet. Blood welled from his chest and back.

The robot stood there impassive, a streak of Danner's blood slanting across its metal chest like a robotic ribbon of honor.

The Fury and the Controller of the Furies stood staring at each other. And the Fury could not, of course, speak, but in Hartz's mind it seemed to.

"Self-defense is no excuse," the Fury seemed to be saying. "We never punish intent, but we always punish action. Any act of murder. Any act of murder…"

Hartz barely had time to drop his revolver in his desk drawer before the first of the clamorous crowd from downstairs came bursting through the door. He barely had the presence of mind to do it, either. He had not really thought the thing through this far.

It was, on the surface, a clear case of suicide. In a slightly unsteady voice he heard himself explaining. Everybody had seen the madman rushing through the office, his Fury at his heels. This wouldn't be the first time a killer and his Fury had tried to get at the Controller, begging him to call off the jailer and forestall the executioner. What had happened, Hartz told his underlings calmly enough, was that the Fury had naturally stopped the man from shooting Hartz. And the victim had then turned his gun upon himself. Powder-burns on his clothing showed it. (The desk was very near the door.) Back-blast in the skin of Danner's hands would show he had really fired a gun.

Suicide. It would satisfy any human. But it would not satisfy the computers.

They carried the dead man out. They left Hartz and the Fury alone, still facing each other across the desk. If anyone thought this was strange, nobody showed it.

Hartz himself didn't know if it was strange or not. Nothing like this had ever happened before. Nobody had ever been fool enough to commit murder in the very presence of a Fury. Even the Controller did not know exactly how the computers assessed evidence and fixed guilt. Should this Fury have been recalled, normally? If Danner's death were really suicide, would Hartz stand here alone now?

He knew the machines were already processing the evidence of what had really happened here. What he couldn't be sure of was whether this Fury had already received its orders and would follow him wherever he went from now on until the hour of his death. Or whether it simply stood motionless, waiting recall.

Well, it didn't matter. This Fury or another was already, in the present moment, in the process of receiving instructions about him. There was only one thing to do. Thank God there was something he could do.

So Hartz unlocked the desk drawer and slid it open, touched the clicking keys he had never expected to use. Very carefully he fed. the coded information, digit by digit, into the computers. As he did, he looked out through the glass wall and imagined he could see down there in the hidden tapes the units of data fading into blankness and the new, false information flashing into existence.

He looked up at the robot. He smiled a little.

"Now you'll forget," he said. "You and the computers. You can go now. I won't be seeing you again."

Either the computers worked incredibly fast-as of course they did-or pure coincidence took over, because in only a moment or two the Fury moved as if in response to Hartz's dismissal. It had stood quite motionless since Danner slid through its arms. Now new orders animated it, and briefly its motion was almost jerky as it changed from one set of instructions to another. It almost seemed to bow, a stiff little bending motion that brought its head down to a level with Hartz's.

He saw his own face reflected in the blank face of the Fury. You could very nearly read an ironic note in that stiff bow, with the diplomat's ribbon of honor across the chest of the creature, symbol of duty discharged honorably. But there was nothing. honorable about this withdrawal. The incorruptible metal was putting on corruption and looking back at Hartz with the reflection of his own face.

He watched it stalk toward the door. He heard it go thudding evenly down the stairs. He could feel the thuds vibrate in the floor, and there was a sudden sick dizziness in him when he thought the whole fabric of society was shaking under his feet.

The machines were corruptible.

Mankind's survival still depended on the computers, and the computers could not be trusted. Hartz looked down and saw that his hands were shaking. He shut the drawer and heard the lock click softly. He gazed at his hands. He felt their shaking echoed in an inner shaking, a terrifying sense of the instability of the world.

A sudden, appalling loneliness swept over him like a cold wind. He had never felt before so urgent a need for the companionship of his own kind. No one person, but people. Just people. The sense of human beings all around him, a very primitive need.

He got his hat and coat and went downstairs rapidly, hands deep in his pockets because of some inner chill no coat could guard against. Halfway down the stairs he stopped dead still.

There were footsteps behind him.

He dared not look back at first. He knew those footsteps. But he had two fears and he didn't know which was worse. The fear that a Fury was after him-and the fear that it was not. There would be a sort of insane relief if it really was, because then he could trust the machines after all, and this terrible loneliness might pass over him and go.

He took another downward step, not looking back. He heard the ominous footfall behind him, echoing his own. He sighed one deep sigh and looked back.

There was nothing on the stairs.