Turbor laughed suddenly - laughed in huge, windy gusts that bounced ringingly off the walls and died in gasps. He shook his head, weakly, and said, "Great Galaxy, this goes on all night. One after another, we put up our straw men to be knocked down. We have fun, but we don't get anywhere. Space! Maybe all planets are the Second Foundation. Maybe they have no planet, just key men spread on all the planets. And what does it matter, since Darell says we have the perfect defense?"

Darell smiled without humor. "The perfect defense is not enough, Turbor. Even my Mental Static device is only something that keeps us in the same place. We cannot remain forever with our fists doubled, frantically staring in all directions for the unknown enemy. We must know not only how to win, but whom to defeat. And there is a specific world on which the enemy exists."

"Get to the point," said Anthor, wearily. "What's your information?"

"Arcadia," said Darell, "sent me a message, and until I got it, I never saw the obvious. I probably would never have seen the obvious. Yet it was a simple message that went: 'A circle has no end.' Do you see?"

"No," said Anthor, stubbornly, and he spoke, quite obviously, for the others.

"A circle has no end," repeated Munn, thoughtfully, and his forehead furrowed.

"Well," said Darell, impatiently, "it was clear to me- What is the one absolute fact we know about the Second Foundation, eh? I'll tell you! We know that Hari Seldon located it at the opposite end of the Galaxy. Homir Munn theorized that Seldon lied about the existence of the Foundation. Pelleas Anthor theorized that Seldon had told the truth that far, but lied about the location of the Foundation. But I tell you that Hari Seldon lied in no particular; that he told the absolute truth.

"But, what is the other end? The Galaxy is a flat, lens-shaped object. A cross section along the flatness of it is a circle, and a circle had no end - as Arcadia realized. We - we, the First Foundation - are located on Terminus at the rim of that circle. We are at an end of the Galaxy, by definition. Now follow the rim of that circle and find the other end. Follow it, follow it, follow it, and you will find no other end. You will merely come back to your starting point-

"And there you will find the Second Foundation."

"There?" repeated Anthor. "Do you mean here?"

"Yes, I mean here!" cried Darell, energetically. "Why, where else could it possibly be? You said yourself that if the Second Foundationers were the guardians of the Seldon Plan, it was unlikely that they could be located at the so-called other end of the Galaxy, where they would be as isolated as they could conceivably be. You thought that fifty parsecs distance was more sensible. I tell you that that is also too far. That no distance at all is more sensible. And where would they be safest? Who would look for them here? Oh, it's the old principle of the most obvious place being the least suspicious.

"Why was poor Ebling Mis so surprised and unmanned by his discovery of the location of the Second Foundation? There he was, looking for it desperately in order to warn it of the coming of the Mule, only to find that the Mule had already captured both Foundations at a stroke. And why did the Mule himself fail. in his search? Why not? If one is searching for an unconquerable menace, one would scarcely look among the enemies already conquered. So the Mind-masters, in their own leisurely time, could lay their plans to stop the Mule, and succeeded in stopping him.

"Oh, it is maddeningly simple. For here we are with our plots and our schemes, thinking that we are keeping our secrecy - when all the time we are in the very heart and core of our enemy's stronghold. It's humorous."

Anthor did not remove the skepticism from his face, "You honestly believe this theory, Dr. Darell?"

"I honestly believe it."

"Then any of our neighbors, any man we pass in the street might be a Second Foundation superman, with his mind watching yours and feeling the pulse of its thoughts."

"Exactly."

"And we have been permitted to proceed all this time, without molestation?"

"Without molestation? Who told you we were not molested? You, yourself, showed that Munn has been tampered with. What makes you think that we sent him to Kalgan in the first place entirely of our own volition - or that Arcadia overheard us and followed him on her own volition? Hah! We have been molested without pause, probably. And after all, why should they do more than they have? It is far more to their benefit to mislead us, than merely to stop us."

Anthor buried himself in meditation and emerged therefrom with a dissatisfied expression. "Well, then, I don't like it. Your Mental Static isn't worth a thought. We can't stay in the house forever and as soon as we leave, we're lost, with what we now think we know. Unless you can build a little machine for every inhabitant in the Galaxy."

"Yes, but we're not quite helpless, Anthor. These men of the Second Foundation have a special sense which we lack. It is their strength and also their weakness. For instance, is there any weapon of attack that will be effective against a normal, sighted man which is useless against a blind man?"

"Sure," said Munn, promptly. "A light in the eyes."

"Exactly," said Darell. "A good, strong blinding light."

"Well, what of it?" asked Turbor.

"But the analogy is clear. I have a Mind Static device. It sets up an artificial electromagnetic pattern, which to the mind of a man of the Second Foundation would be like a beam of light to us. But the Mind Static device is kaleidoscopic. It shifts quickly and continuously, faster than the receiving mind can follow. All right then, consider it a flickering light; the kind that would give you a headache, if continued long enough. Now intensify that light or that electromagnetic field until it is blinding - and it will become a pain, an unendurable pain. But only to those with the proper sense; not to the unsensed."

"Really?" said Anthor, with the beginnings of enthusiasm. "Have you tried this?"

"On whom? Of course, I haven't tried it. But it will work."

"Well, where do you have the controls for the Field that surrounds the house? I'd like to see this thing."

"Here." Darell reached into his jacket pocket. It was a small thing, scarcely bulging his pocket. He tossed the black, knob-studded cylinder to the other.

Anthor inspected it carefully and shrugged his shoulders. "It doesn't make me any smarter to look at it. Look Darell, what mustn't I touch? I don't want to turn off the house defense by accident, you know."

"You won't," said Darell, indifferently. "That control is locked in place." He flicked at a toggle switch that didn't move.

"And what's this knob?"

"That one varies rate of shift of pattern. Here - this one varies the intensity. It's that which I've been referring to."

"May I-" asked Anthor, with his finger on the intensity knob. The others were crowding close.

"Why not?" shrugged DarelI. "It won't affect us."

Slowly, almost wincingly, Anthor turned the knob, first in one direction, then in another. Turbor was gritting his teeth, while Munn blinked his eyes rapidly. It was as though they were keening their inadequate sensory equipment to locate this impulse which could not affect them.

Finally, Anthor shrugged and tossed the control box back into Darell's lap. "Well, I suppose we can take your word for it. But it's certainly hard to imagine that anything was happening when I turned the knob."

"But naturally, Pelleas Anthor," said Darell, with a tight smile. "The one I gave you was a dummy. You see I have another." He tossed his jacket aside and seized a duplicate of the control box that Anthor had been investigating, which swung from his belt.

"You see," said Darell, and in one gesture turned the intensity knob to maximum.

And with an unearthly shriek, Pelleas Anthor sank to the floor. He rolled in his agony; whitened, gripping fingers clutching and tearing futilely at his hair.

Munn lifted his feet hastily to prevent contact with the squirming body, and his eyes were twin depths of horror. Semic and Turbor were a pair of plaster casts; stiff and white.

Darell, somber, turned the knob back once more. And Anthor twitched feebly once or twice and lay still. He was alive, his breath racking his body.

"Lift him on to the couch," said Darell, grasping the young man's head. "Help me here."

Turbor reached for the feet. They might have been lifting a sack of flour. Then, after long minutes, the breathing grew quieter, and Anthor's eyelids fluttered and lifted. His face was a horrid yellow; his hair and body was soaked in perspiration, and his voice, when he spoke, was cracked and unrecognizable.

"Don't," he muttered, "don't! Don't do that again! You don't know- You don't know- Oh-h-h." It was a long, trembling moan.

"We won't do it again," said Darell, "if you will tell us the truth. You are a member of the Second Foundation?"

"Let me have some water," pleaded Anthor.

"Get some, Turbor," said Darell, "and bring the whiskey bottle."

He repeated the question after pouring a jigger of whiskey and two glasses of water into Anthor. Something seemed to relax in the young man-

"Yes," he said, wearily. "I am a member of the Second Foundation."

"Which," continued Darell, "is located on Terminus - here?"

"Yes, yes. You are right in every particular, Dr. Darell."

"Good! Now explain what's been happening this past half year. Tell us!"

"I would like to sleep," whispered Anthor.

"Later! Speak now!"

A tremulous sigh. Then words, low and hurried. The others bent over him to catch the sound, "The situation was growing dangerous. We knew that Terminus and its physical scientists were becoming interested in brain-wave patterns and that the times were ripe for the development of something like the Mind Static device. And there was growing enmity toward the Second Foundation. We had to stop it without ruining SeIdon's Plan.

"We... we tried to control the movement. We tried to join it. It would turn suspicion and efforts away from us. We saw to it that Kalgan declared war as a further distraction. That's why I sent Munn to Kalgan. Stettin's supposed mistress was one of us. She saw to it that Munn made the proper moves-"

"Callia is-" cried Munn, but Darell waved him silent.

Anthor continued, unaware of any interruption, "Arcadia followed. We hadn't counted on that - can't foresee everything - so Callia maneuvered her to Trantor to prevent interference. That's all. Except that we lost."

"You tried to get me to go to Trantor, didn't you?" asked Darell.

Anthor nodded, "Had to get you out of the way. The growing triumph in your mind was clear enough. You were solving the problems of the Mind Static device."

"Why didn't you put me under control?"

"Couldn't... couldn't. Had my orders. We were working according to a Plan. If I improvised, I would have thrown everything off. Plan only predicts probabilities... you know that... like Seldon's Plan." He was talking in anguished pants, and almost incoherently. His head twisted from side to side in a restless fever. "We worked with individuals... not groups... very low probabilities involved... lost out. Besides... if control you... someone else invent device... no use... had to control times... more subtle... First Speaker's own plan... don't know all angles... except... didn't work a-a-a-" He ran down.

Darell shook him roughly, "You can't sleep yet. How many of you are there?"

"Huh? Whatjasay... oh... not many... be surprised fifty... don't need more."

"All here on Terminus?"

"Five... six out in Space... like Callia... got to sleep."

He stirred himself suddenly as though to one giant effort, and his expressions gained in clarity. It was a last attempt at self-justification, at moderating his defeat.

"Almost got you at the end. Would have turned off defenses and seized you. Would have seen who was master. But you gave me dummy controls... suspected me all along-"

And finally he was asleep.

Turbor said, in awed tones, "How long did you suspect him, Darell?"

"Ever since he first came here," was the quiet response. "He came from Kleise, he said. But I knew Kleise; and I knew on what terms we parted. He was a fanatic on the subject of the Second Foundation and I had deserted him. My own purposes were reasonable, since I thought it best and safest to pursue my own notions by myself. But I couldn't tell Kleise that; and he wouldn't have listened if I had. To him, I was a coward and a traitor, perhaps even an agent of the Second Foundation. He was an unforgiving man and from that time almost to the day of his death he had no dealings with me. Then, suddenly, in his last few weeks of life, he writes me - as an old friend - to greet his best and most promising pupil as a co-worker and begin again the old investigation.

"It was out of character. How could he possibly do such a thing without being under outside influence, and I began to wonder if the only purpose might not be to introduce into my confidence a real agent of the Second Foundation. Well, it was so-"

He sighed and closed his own eyes for a moment.

Semic put in hesitantly, "What will we do with all of them... these Second Foundation fellas?"

"I don't know," said Darell, sadly. "We could exile them, I suppose. There's Zoranel, for instance. They can be placed there and the planet saturated with Mind Static. The sexes can be separated, or, better still, they can be sterilized - and in fifty years, the Second Foundation will be a thing of the past. Or perhaps a quiet death for all of them would be kinder."

"Do you suppose," said Turbor, "we could learn the use of this sense of theirs. Or are they born with it, like the Mule."

"I don't know. I think it is developed through long training, since there are indications from encephalography that the potentialities of it are latent in the human mind. But what do you want that sense for? It hasn't helped them."

He frowned.

Though he said nothing, his thoughts were shouting.

It had been too easy - too easy. They had fallen, these invincibles, fallen like book-villains, and he didn't like it.

Galaxy! When can a man know he is not a puppet? How can a man know he is not a puppet?

Arcadia was coming home, and his thoughts shuddered away from that which he must face in the end.

She was home for a week, then two, and he could not loose the tight check upon those thoughts. How could he? She had changed from child to young woman in her absence, by some strange alchemy. She was his link to life; his link to a bittersweet marriage that scarcely outlasted his honeymoon.

And then, late one evening, he said as casually as he could, "Arcadia, what made you decide that Terminus contained both Foundations?"

They had been to the theater; in the best seats with private trimensional viewers for each; her dress was new for the occasion, and she was happy.

She stared at him for a moment, then tossed it off. "Oh, I Don't know, Father. It just came to me."

A layer of ice thickened about Dr. Darell's heart.

"Think," he said, intensely. "This is important. What made you decide both Foundations were on Terminus."

She frowned slightly. "Well, there was Lady Callia. I knew she was a Second Foundationer. Anthor said so, too."

"But she was on Kalgan," insisted Darell. "What made you decide on Terminus?"

And now Arcadia waited for several minutes before she answered. What had made her decide? What had made her decide?

She had the horrible sensation of something slipping just beyond her grasp.

She said, "She knew about things - Lady Callia did - and must have had her information from Terminus. Doesn't that sound right, Father?

But he just shook his head at her.

"Father," she cried, "I knew. The more I thought, the surer I was. It just made sense."

There was that lost look in her father's eyes, "It's no good, Arcadia. Its no good. Intuition is suspicious when concerned with the Second Foundation. You see that, don't you? It might have been intuition - and it might have been control!"

"Control! You mean they changed me? Oh, no. No, they couldn't." She was backing away from him. "But didn't Anthor say I was right? He admitted it. He admitted everything. And you've found the whole bunch right here on Trantor. Didn't you? Didn't you?" She was breathing quickly.

"I know, but- Arcadia, will you let me make an encephalographic analysis of your brain?'

She shook her head violently, "No, no! I'm too scared."

"Of me, Arcadia? There's nothing to be afraid of. But we must know. You see that, don't you?"

She interrupted him only once, after that. She clutched at his arm just before the last switch was thrown. "What if I am different, Father? What will you have to do?"

"I won't have to do anything, Arcadia. If you're different, we'll leave. Well go back to Trantor, you and I, and... and we won't care about anything else in the Galaxy."

Never in Darell's life had an analysis proceeded so slowly, cost him so much, and when it was over, Arcadia huddled down and dared not look. Then she heard him laugh and that was information enough. She jumped up and threw herself into his opened arms.

He was babbling wildly as they squeezed one another, "The house is under maximum Mind Static and your brain-waves are normal. We really have trapped them, Arcadia, and we can go back to living."

"Father," she gasped, "can we let them give us medals now?"

"How did you know I'd asked to be left out of it?" He held her at arm's mind; you know everything. All right, you can have your medal on a platform, with speeches."

"And Father?"

"Yes?"

"Can you call me Arkady from now on."

"But- Very well, Arkady."

Slowly the magnitude of the victory was soaking into him and saturating him. The Foundation - the First Foundation - now the only Foundation - was absolute master of the Galaxy. No further barrier stood between themselves and the Second Empire - the final fulfillment of Seldon's Plan.

They had only to reach for it-

Thanks to-