Ever since he had first set foot into his mind, some ten hours ago, they had been on his trail, but for some reason he had been unable to bring himself to go back and find out who they were and what they wanted. Hence he was as vexed with himself as he was with them.

After resting for a few minutes, he descended the hill and started across the Deneb 1 wasteland. It was a remarkably detailed materialization, and his quarry's footprints stood out clearly in the duplicated sand.

Sabrina York did not even know the rudiments of the art of throwing off a mind-tracker. It would have done her but little good if she had, for twelve years as a psycheye had taught Blake all the tricks. Probably she had taken it for granted that the mere act of hiding out in her tracker's mind was in itself a sufficient guarantee of her safety. After all, she had no way of knowing that he had discovered her presence.

Mind-country was as temporally inconsecutive as it was topographically incongruous, so Blake was not surprised when the Deneb 1 wasteland gave way to an expanse of boyhood meadow. Near the meadow was the house where Blake had lived at a much later date. In reality, the places were as far apart in miles as they were in years, but here in the country of his mind they existed side by side, surrounded by heterogeneous landscapes from all over the civilized sector of the galaxy and by the sharply demarcated spectra of a hundred different suns. A few of the suns were in the patchwork sky—Sirius, for example, and its twinkling dwarf companion. Most of them, however, were present only in their remembered radiance. To add to the confusion, scattered night memories interrupted the hodge-podge horizon with columns of darkness, and here and there the gray column of a dawn or dusk memory showed.

The house was flanked on one side by a section of a New Earth spaceport and on the other by an excerpt of an Ex-earth city-block. Behind it flowed a brief blue stretch of Martian waterway.

Sabrina's footsteps led up to the front door, and the door itself was ajar. Perhaps she was still inside. Perhaps she was watching him even now through one of the remembered windows. He scanned them with a professional eye, but saw no sign of her.

Warily he stepped inside, adjusting the temperature of his all-weather jacket to the remembered air-conditioning. His father was sitting in the living room, smoking, and watching 3V. He had no awareness of Blake. At Blake's entry he went right on smoking and watching as though the door had neither opened nor closed. He would go right on smoking and watching till Blake died and the conglomeration of place-times that constituted Blake's mind-world ceased to be. Ironically, he was watching nothing. The 3V program that had been in progress at the time of the unconscious materialization had failed to come through.

The memory was a treasured one—the old man had perished in a 'copter crash several years ago—and for a long while Blake did not move. He had never been in his own mind before. Consequently he was more affected than he might otherwise have been. Finally, stirring himself, he walked out into the kitchen. On a shelf above the sink stood a gaily colored box of his mother's favorite detergent with a full-length drawing of Vera Velvetskin, the company's blond and chic visual symbol, on the front. His mother was standing before the huge automatic range, preparing a meal she had served twenty-three years ago. He regarded her with moist eyes. She had died a dozen years before his father, but the wound that her death had caused had never healed. He wanted to go up behind her and touch her shoulder and say, "What's for supper, mom?" but he knew it would do no good. For her he had no reality, not only because he was far in her future, but because in his mind-world she was a mortal and he, a god—a picayune god, perhaps, but a real one.

As he was about to turn away, the name-plate on the range caught his eye, and thinking that he had read the two words wrong, he stepped closer so that he could see them more clearly. No, he had made no mistake: the first word was "Sabrina", and the second was "York".

He stepped back. Odd that a kitchen range should have the same name as his quarry. But perhaps not unduly so. Giving appliances human names had been common practice for centuries. Even a name like "Sabrina York", while certainly not run-of-the-mill, was bound to be duplicated in real life. Nevertheless a feeling of uneasiness accompanied him when he left the kitchen and climbed the stairs to the second floor.

He went through each room systematically, but saw no sign of Sabrina York. He lingered for some time in his own room, wistfully watching his fifteen-year-old self lolling on the bed with a dog-eared copy of The Galaxy Boys and the Secret of the Crab Nebula, then he stepped back out into the hall and started to descend the stairs.

At the head of the stairs a narrow window looked out over the front yard and thence out over the meadow. He glanced absently through the panes, and came to an abrupt halt. His three pursuers were wading through the long meadow grass less than a quarter of a mile away—not close enough as yet for him to be able to make out their faces, but close enough for him to be able to see that two of them were wearing dresses and that the third had on a blue skirt and blouse, and a kepi to match. He gasped. It simply hadn't occurred to him that his pursuers might be women. To his consternation he discovered that he was even more loath to go back and accost them than he had been before. He actually had an impulse to flee.

He controlled it and descended the stairs with exaggerated slowness, leaving the house by way of the back door. He picked up Sabrina's trail in the back yard and followed it down to the Martian waterway and thence along the bank to where the waterway ended and a campus began. Not the campus of the university which he had visited two days ago to attend his protegee's graduation. It was not a place-time that he cared to revisit, nor a moment that he cared to relive, but Sabrina's trail led straight across the artificially stunted grass toward the little bench where he and Deirdre Eldoria had come to talk after the ceremony was over. He had no choice.

The bench stood beneath a towering American elm whose feathery branches traced green arabesques against the blue June sky. A set of footprints slightly deeper than its predecessors indicated that Sabrina had paused by the trunk. Despite himself Blake paused there too. Pain tightened his throat when he looked at Deirdre's delicate profile and copper-colored hair, intensified when he lowered his eyes to the remembered blueness of her graduation dress. The diamond brooch that he had given her as a graduation present, and which she had proudly pinned upon her bodice for the whole wide world to see, made him want to cry. His self-image of two weeks ago shocked him. There were lines on the face that did not as yet exist, and the brown hair was shot with streaks of gray that had yet to come into being. Lord, he must have been feeling old to have pictured himself like that!

Deirdre was speaking. "Yes," she was saying, "at nine o'clock. And I should very much like for you to come."

Blake Past shook his head. "Proms aren't for parents. You know that as well as I do. That young man you were talking with a few minutes ago—he's the one who should take you. He'd give his right arm for the chance."

"I'll thank you not to imply that you're my father. One would think from the way you talk that you are centuries old!"

"I'm thirty-eight," Blake Past said, "and while I may not be your father, I'm certainly old enough to be. That young man—"

A pink flush of anger climbed into Deirdre Eldoria's girlish cheeks. "What right has he got to take me! Did he scrimp and go without in order to put me through high school and college? Has he booked passage for me to New Earth and paid my tuition to Trevor University?"

"Please," Blake Past said, desperation deepening his voice. "You're only making everything worse. After majoring in Trevorism, you certainly ought to realize by now that there was nothing noble about my buying you after Eldoria died. I only did it to ease my conscience—"

"What do you know about conscience?" Deirdre demanded. "Conscience is a much more complex mechanism than most laymen realize. Guilt feelings aren't reliable criteria. They can stem from false causes—from ridiculous things like a person's inability to accept himself for what he is." Abruptly she dropped the subject. "Don't you realize, Nate," she went on a little desperately, "that I'm leaving tomorrow and that we won't see each other again for years and years?"

"I'll come to New Earth to visit you," Blake said. "Venus is only a few days distant on the new ships."

She stood up. "You won't come—I know you won't." She stamped her foot. "And you won't come to the prom either. I know that too. I knew it all along. Sometimes I'm tempted to—" Abruptly she broke off. "Very well then," she went on, "I'll say good-by now then."

Blake Past stood up too. "No, not yet. I'll walk back to the sorority house with you."

She tossed her head, but the sadness in her tarn-blue eyes belied her hauteur. "If you wish," she said.

Blake Present watched them set out side by side toward the remembered halls of learning that showed in the distance. There had been other people present on the campus that afternoon, but as they had failed to register on Blake Past's mind, they did not exist for Blake Present. All that existed for Blake Present were the diminishing figures of the girl and the man, and the pain that was constricting his throat.

Wretchedly he turned away. As he did so he saw the three shadows lying at his feet and knew that his pursuers had at last caught up to him.

His first reaction when he faced them was amazement. His next reaction was shock. His third was fear.

His amazement resulted from recognition. One of the three women arrayed before him was Miss Stoddart, his boyhood Sunday-school teacher. Standing next to her in a familiar blue uniform was Officer Finch, the police woman who had maintained law and order in the collective elementary school he had attended. Standing next to Officer Finch was blond and chic Vera Velvetskin, whose picture he had seen on box after countless box of his mother's favorite detergent.

His shock resulted from the expressions on the three faces. Neither Miss Stoddart nor Officer Finch ever particularly liked him, but they had never particularly disliked him either. This Miss Stoddart and this Officer Finch disliked him, though. They hated him. They hated him so much that their hatred had thinned out their faces and darkened their eyes. More shocking yet, Vera Velvetskin, who had never existed save in some copywriter's mind, hated him too. In fact, judging from the greater thinness of her face and the more pronounced darkness of her eyes, she hated him even more than Miss Stoddart and Officer Finch did.

His fear resulted from the realization that his mind-world contained phenomena it had no right to contain—not if he was nearly as well-adjusted as he considered himself to be. The three women standing before him definitely were not memory-images. They were too vivid, for one thing. For another, they were aware of him. What were they, then? And what were they doing in his mind?

He asked the two questions aloud.

Three arms were raised and three forefingers were pointed accusingly at his chest. Three pairs of eyes burned darkly. "You ask us that?" Miss Stoddart said. "Callous creature who did a maiden's innocence affront!" said Officer Finch. "And sought sanctuary in ill-fitting robes of righteousness!" said Vera Velvetskin. The three faces moved together, blurred and seemed to blend into one. The three voices were raised in unison: "You know who we are, Nathan Blake. You know who we are!"

Blake stared at them open-mouthed. Then he turned and fled.

It had taken man a long time to discover that he was a god in his own right and that he too was capable of creating universes. Trivial universes, to be sure, when compared with the grandeur and scope of the objective one, and peopled with ghosts instead of human beings; but universes nonetheless.

The discovery came about quite by accident. After projecting himself into a patient's memory one day, a psychologist named Trevor suddenly found himself clinging to the slope of a traumatically distorted mountain. His patient was beside him.

The mountain proved to be an unconscious memory-image out of the patient's boyhood, and its country proved to be the country of the patient's mind. After many trials and errors, Trevor managed to get both himself and his patient back to the objective world, and not long afterward he was able to duplicate the feat on another case.

The next logical step was to enter his own mind, and this he also succeeded in doing.

It was inevitable that Trevor should write a book about his discovery and set about founding a new school of psychology. It was equally inevitable that he should acquire enemies as well as disciples. However, as the years passed and the new therapy which he devised cured more and more psychoses, the ranks of his disciples swelled and those of his enemies shrank. When, shortly before his death, he published a paper explaining how anyone could enter his or her own mind-world at will, his niche in the Freudian hall of fame was assured.

The method employed an ability that had been evolving in the human mind for millennia—the ability to project oneself into a past moment—or, to use Trevor's term, a past "place-time." Considerable practice was required before the first transition could be achieved, but once it was achieved, successive transitions became progressively easier. Entering another person's mind-world was of course a more difficult undertaking, and could be achieved only after an intensive study of a certain moment in that person's past. In order to return to the objective world, it was necessary in both cases to locate the most recently materialized place-time and take one step beyond it.

By their very nature, mind-countries were confusing. They existed on a plane of reality that bore no apparent relationship to the plane of the so-called objective universe. In fact, so far as was known, this secondary—or subjective—reality was connected to so-called true reality only through the awareness of the various creators. In addition, these countries had no outward shape in the ordinary sense of the word, and while most countries contained certain parallel images, these images were subject to the interpretation of the individual creator. As a result they were seldom identical.

It was inevitable that sooner or later some criminal would hit upon the idea of hiding out in his own mind-world till the statute of limitations that applied to his particular crime ran out, and it was equally inevitable that others should follow suit. Society's answer was the psyche-police, and the psyche-police hadn't been in action very long before the first private psycheye appeared.

Blake was one of a long line of such operators.

So far as he knew, the present case represented the first time a criminal had ever hidden out in the pursuer's mind. It would have been a superb stratagem indeed if, shortly after her entry, Sabrina York had not betrayed her presence. For her point of entry she had used the place-time materialization of the little office Blake had opened on Ex-earth at the beginning of his career. Unaccountably she had ransacked it before moving into a co-terminous memory-image.

Even this action wouldn't have given her away, however, if the office hadn't constituted a sentimental memory. Whenever Blake accepted a case he invariably thought of the bleak and lonely little room with its thin-gauge steel desk and battered filing cabinets, and when he had done so after accepting his case—or was it before? He couldn't quite remember—the mental picture that had come into his mind had revealed open drawers, scattered papers and a general air of disarray.

He had suspected the truth immediately, and when he had seen the woman's handkerchief with the initials "SB" embroidered on it lying by one of the filing cabinets he had known definitely that his quarry was hiding out in his mind. Retiring to his bachelor quarters, he had entered at the same place-time and set off in pursuit.

Her only advantage lost, Sabrina York was now at his mercy. Unless she discovered his presence and was able to locate his most recently materialized place-time before he over-took her, her capture was assured.

Only two things bothered Blake. The little office was far in his past, and it was unlikely that anyone save the few intimate acquaintances whom he had told about it were aware that it had ever existed. How, then, had a total stranger such as Sabrina York learned enough about it to enable her to use it as a point of entry?

The other thing that bothered him was of a much more urgent nature. He had been in enough minds and he had read enough on the subject of Trevorism to know that people were sometimes capable of creating beings considerably higher on the scale of mind-country evolution than ordinary memory-ghosts. One woman whom he had apprehended in her own mind had created a walking-talking Virgin Mary who watched over her wherever she went. And once, after tracking down an ex-enlisted man, he had found his quarry holed up in the memory-image of an army barracks with a ten-star general waiting on him hand and foot. But these, and other, similar, cases, had to do with mal-adjusted people, and moreover, the super-image in each instance had been an image that the person involved had wanted to create. Therefore, even assuming that Blake was less well-adjusted than he considered himself to be, why had he created three such malevolent super-images as Miss Stoddart, Officer Finch, and Vera Velvetskin?

They followed him off the campus into a vicarious memory-image of Walden Pond, Thoreau's shack, and the encompassing woods. Judging from the ecstatic "oh's" and "ah's" they kept giving voice to, the place delighted them. Once, glancing back over his shoulder, he saw them standing in front of Thoreau's shack, looking at it as though it were a doll's house. Not far away, Thoreau was sitting in under a tall pine, gazing up into the branches at a bird that had come through only as a vague blur of beak and feathers.

Blake went on. Presently the Walden Pond memory-image gave way to a memory-image of an English park which the ex-Earth government had set aside as a memorial to the English poets and which had impressed Blake sufficiently when he had visited it in his youth to have found a place for itself in the country of his mind. It consisted of reconstructions of famous dwellings out of the lives of the poets, among them, a dwelling out of the life of a poet who was not in the strictest sense of the word English at all—the birthplace of Robert Burns. Oddly enough, it was Burns's birthplace that had impressed Blake most. Now the little cottage stood out in much more vivid detail than any of the other famous dwellings.

Sabrina York must have been attracted to the place, for her footprints showed that she had turned in at the gate, walked up the little path and let herself in the door.

They also showed that she had left by the same route, so there was no reason for Blake to linger. As a matter of fact, the fascination that had brought the place into being had been replaced by an illogical repugnance. But repugnance can sometimes be as compelling a force as fascination, and Blake not only lingered but went inside as well.

He remembered the living room distinctly—the flagstone floor, the huge grill-fronted hearth, the deeply recessed window, the rack of cups and platters on the wall; the empty straight-backed chair standing sternly in a corner, the bare wooden table—

He paused just within the doorway. The chair was no longer empty, the table no longer bare.

A man sat on the former and a bottle of wine stood on the latter. Moreover, the room showed signs of having been lived in for a long time. The floor was covered with tracked-in dirt and the walls were blackened from smoke. The grill-work of the hearth was begrimed with grease.

Whatever else he might be the man sitting at the table was not an image out of the past. He was too vividly real. He was around Blake's age, and about Blake's height and build. However, he was given to fat. His paunch contrasted jarringly with Blake's trim waist. His vaguely familiar face was swollen—probably from the wine he had drunk—and his too-full cheeks were well on the way to becoming jowls. His bloodshot eyes were underscored with shadows, and his clothing consisted of odds and ends out of Blake's past: a tattered, too-tight pullover with the letter "L" on the front, a pair of ragged red-plaid hunting breeches and a pair of cracked riding-boots.

Blake advanced across the room and picked up the bottle. One sniff told him that it came from a memory-image of a Martian wine-cellar. He set the bottle back down. "Who are you?" he demanded.

The man looked up at him sardonically. "Call me Smith," he said. "If I told you who I really am, you wouldn't believe me."

"What are you doing in my mind?"

"You should know the answer to that one. You put me here."

Blake stared "Why, I've never even seen you before!"

"Granted," Smith said. "But you used to know me. As a matter of fact, you and I used to get along together famously." He reached around and got a cup off the wall-rack. "Pull up a chair and have a drink. I've been expecting you."

Bewildered, Blake sat but shoved the cup aside. "I don't drink," he said.

"That's right," Smith said. "Stupid of me to forget." He took a swig out of the bottle, set it back down. "Let's see, it's been seven years now. Right?"

"How the devil did you know?"

Smith sighed. "Who should know better than I? Who indeed? But I guess I can't kick too much. You certainly materialized enough of the stuff in your—shall we say 'wilder'?—days." He shook his head. "No, I can't say I've suffered in that respect."

Comprehension came to Blake then. He had heard of the parasites who lived in other person's minds, but this was the first time he had ever happened to run across one. "Why, you're nothing but a mind-comber," he said. "I should have guessed!"

Smith looked hurt. "You do me a grave injustice, friend. A very grave injustice. And after my being so considerate of this cottage and using the back door and everything! The young lady who stopped by a little while ago was much more understanding than you are."

"You talked with her then?" Blake asked. He suppressed a shudder. For some reason it horrified him that his quarry should be aware that so despicable a creature inhabited his mind. "What—what does she look like?"

"You know what she looks like."

"But I don't. I took the case on such short notice that I didn't have a chance to get a picture or even a description of her."

Smith regarded him shrewdly. "What did she do?"

"She murdered her father," Blake said.

Smith guffawed. "I should have known it would be something like that. Ties in perfectly. By the way, what's her name?"

"Sabrina York—not that it's any of your business."

"Oh, but it is my business—as much my business as yours. As a matter of fact, I'm going to help you find her."

Blake stood up. "No, you're not," he said. "You're going to get out of my mind and you're going to stay out—"