“I know that Sacarsi and Wolverstein haven’t been heard of since they contacted you,” he conceded.

“No, for they went through their doors; they found — the worlds they had always unconsciously sought. It is as I have told you. One takes his seat upon the Siege and before him opens that existence in which his spirit, his mind — his soul if you wish to call it that — is at home. And he goes forth to seek his fortune there.”

“Why haven’t you tried it yourself?” That was to Simon the weak point in the other’s story. If Petronius possessed the key to such a door, why had he not used it himself?

“Why?” The doctor stared down at the two plump hands resting on his knees. “Because there is no return — and only a desperate man chooses an irrevocable future. In this world we always cling to the belief that we can control our lives, make our own decisions. But through there, we have made a choice which cannot be cancelled. I use words, many words, but at this moment I cannot seem to choose them rightly to express what I feel. There have been many Guardians of the Siege — only a few of them have used it for themselves. Perhaps… some day…but as yet I have not the courage.”

“So you sell your services to the hunted? Well, that is one way of making a living. A list of your clients might make interesting reading.”

“Correct! I have had some very famous men apply for assistance. Especially at the close of the war. You might not believe the identity of some who sought me out then, after fortune’s wheel spun against them.”

Simon nodded. “There were’some notable gaps in the war criminal captures,” he remarked. “And some odd worlds your stone must have opened if your tale is true.” He arose and stretched. Then went to the table and counted out the money he took from his belt. Old bills, most of them, dirty, with a greasy film as if the business they had been used for had translated some of its slime to their creased surfaces. There remained in his hand a single coin. Simon spun it in the air and let it ring down on the polished wood. The engraved eagle lay up. He looked at it for a moment and then picked it up again.

“This I take.”

“A luck piece?” The doctor was busy with the bills, stacking them into a tidy pile. “By all means retain it then; a man can never have too much luck. And now, I dislike speeding the parting guest, but the power of the Siege is limited. And the proper moment is all-important. This way, please.”

He might have been ushering one into a dentist’s office, or to a board meeting, Simon thought. And perhaps he was a fool to follow.

The rain had stopped, but it was still dark in the square box of yard behind the old house. Petronius pushed a switch and a light fanned out from the back door. Three gray stones formed an arch which topped Simon’s head by a few scant inches. And before that lay a fourth stone, as unpolished, unshaped and angular as the others. Beyond that arch was a wooden fence, high, unpainted, rotted with age, grimed with city dirt, and a foot or two of sour slum soil, nothing else.

Simon stood for a long moment, inwardly sneering at his half-belief of a few moments earlier. Now was the time for Sammy to appear and Petronius to earn his real fee.

But the doctor had taken his stand to one side of the clock on the ground. He indicated it with a forefinger.

“The Siege Perilous. If you will just take your seat there, Colonel — it is almost time.”

A grin, without humor, to underline his own folly, twisted Simon’s thin-lipped mouth, as he straddled the stone and then stood for an instant partly under that arch before he sat down. There was a rounded depression to fit his hips. Curiously, with a sense of foreboding, he put out his hands. Yes, there were two other, smaller hollows to hold his palms, as Petronius had promised.

Nothing happened. The wooden fence, the strip of musty earth remained. He was about to stand up when—

“Now!” Petronius’ voice fluted in a word which was half call.

There was a swirling within the stone arch, a melting.

Simon looked out across a stretch of moorland which lay under a gray dawn sky. A fresh wind laden with a strange, invigorating scent fingered his hair. Something within him straightened like a leashed hound to trace that wind to its source, run across that moorland.

“Your world, Colonel, and I wish you the best of it!”

He nodded absently, no longer interested in the little man who called to him. This might be an illusion, but it drew him as nothing else ever had in his life. Without a word of farewell Simon arose and strode beneath the arch.

There was an instant of extreme panic — such fear as he had never imagined could exist, worse than any physical pain — as if the universe had been wrenched brutally apart and he had been spilled out into an awful nothingness. Then he sprawled face down on thick wiry turf.

The dawn light did not mean sun to come, for there was a thick mist filling the air. Simon got to his feet and glanced back over his shoulder. Two rough pillars of reddish rock stood there, between them no city yard but a stretch of the same gray-green moor running on and on into a wall of fog. Petronius had been right: this was no world he knew.

He was shivering. Though he had brought his top coat with him, he did not have his hat, and the moisture plastered his hair to his skull, trickled from scalp to neck and cheek. He needed shelter — some goal. Slowly Simon made a complete turn. No building showed within the rim of the horizon. With a shrug he chose to walk straight away from the rock pillars; one direction was as good as another.

As he plodded across the soggy turf the sky grew lighter, the mist lifted, and the character of the land changed slowly. There were more outcrops of the red stone, the rolling ground held more sharp rises and descents. Before him, how many miles away he could not judge, a broken line cut the sky, suggesting heights to come. And the meal he had treated himself to was many hours in the past. He twisted a leaf from a bush, chewed it absently, finding the flavor pungent but not unpleasant. Then he heard the noise of the hunt.

A horn called in a series of ascending notes, to be answered by a yapping and a single muffled shout. Simon began to trot. When he came out on the lip of a ravine he was certain that the clamor came from the other side of that cut, and was heading in his direction. With the caution of past commando training, he went to earth between two boulders.

The woman was the first to break from the cover of the scrub brush on the opposite bank. She sprinted, her long legs holding to the steady, dogged pace of one who has had a long chase behind, an even more distant goal ahead. At the edge of the narrow valley she hesitated to look back.

Against the grayish-green of the vegetation her slim ivory body, hardly concealed by the tatters which were her only covering, seemed to be spotlighted by the wan light of the dawn. With an impatient gesture she pushed back strands of her long black hair, ran her hands across her face. Then she began to work her way along the crest of the slope, hunting for a path down.

The horn pealed and the yapping answered it. She started convulsively and Simon half arose out of his hiding place as he suddenly realized that in that grim hunt she must be the quarry.

He dropped to one knee again as she jerked one other rags free from a thorn bush. The force of that impatient tug sent her skidding over the rim. Even then she did not scream, but her hands grabbed for a bush as she went forward, and its branches held. As she struggled for footing the hounds burst into view.

They were thin, white animals, their lanky bodies turning with almost boneless fluidity as they came to the edge of the valley wall. With sharp noses pointed down at the woman, they gave triumphant tongue in wailing howls.