"They have magnetic power," said Gary. "They ought to be able to give you all you need."

The old man's eyes were twinkling. "I am remembering the Hellhounds," he said. "The ones who would have the universe destroyed. I cannot seem to like them. It seems to me that something should be done about them."

"But what?" asked Gary. "They seem to be all-powerful. By the time we get back they may have battered the city into a mass of ruins."

The oldster nodded almost sleepily, but his eyes were glowing.

"We have had ones like that in our history," he said. "Ones who overrode the nations and imposed their will, standing in the way of progress. But always someone found something that would break them. Someone found a greater weapon or a greater strength and they went their way. Their names and works were dust and they were forgotten and the civilization that they sought to mold to their own selfish ends went on as if they had never been."

"But I don't see…" began Gary, and then suddenly he did — as clearly as light. He smote his knee and yelled his enthusiasm.

"Of course," he cried. "We have a weapon. A weapon that could wipe them out. The fifth-dimensional energy!"

"Certainly you have," said the old man.

"That would be barbarous," protested Caroline.

"Barbarous!" shouted Gary. "Isn't it barbarous to want to see the universe destroyed so the Hellhounds can go back to the beginning and take it over, control it, dominate it, take over galaxy after galaxy as a new universe is born? Shape it to their needs and desires. Hold in thrall every bit of life that develops on every cooling planet. Become the masters of the universe."

"We must hurry, then," said Caroline. "We must get back. Minutes count. We still may be able to save the Engineers and the universe, wipe out the Hellhounds."

She rose impatiently to her feet.

The old man protested. "You would go so soon?" he asked. "You would not stay and eat with me? Or tell me more about this place at the edge of the universe? Or let me tell you strange things that I know you would be glad to hear?"

Gary hesitated. "Maybe we could stay a while," he suggested.

"No," said Caroline. "We must go."

"Listen," said Gary to the old man, "why don't you come along with us? We'd be glad to have you. We could use you in the fight. There are things that you could tell us that would help."

The old man shook his bead. "I cannot go," he said. "For, you see, you are right. I may be only a shadow. A very substantial shadow, perhaps, but still just a shadow of probability. You can come to me, but I can't go back with you. If I left this planet I might puff into nothingness, revert to the non-existence of the thing that never was."

He hesitated. "But there's something," he said, "that makes me suspect I am not a shadow… that this is actuality, that the Earth will follow the course history tells me it has followed."

"What is that?" asked Gary.

"It is a thing," the old man said, "that I cannot tell you."

"Perhaps we can come back and see you again," said Caroline. "After all this trouble is over."

"No, my child," he said. "You will never come, for ours are lives that never should have met. You represent the beginning and I represent the end. And I am proud that the Earth's last man could have been of service to one of the beginners."

They fastened down their helmets and walked toward the door.

"I will walk with you to your ship," said the old man. "I do not walk a great deal now, for the cold and the thin air bother me. I must be getting old."

Their feet whispered through the sand and the wind keened above the desert, a shrill-voiced wind that played an eternal overture for the stage of desolation old Earth had become.

"I live with ghosts," said the old man as they walked toward the ship. "Ghosts of men and events and great ideals that built a mighty race.

"Probably you wonder that I resemble a man so much. Perhaps you thought that men, in time to come, would evolve into specialized monstrosities — great, massive brains that had lost the power of locomotion, or bundles of emotional reactions, unstable as the very wind, or foolish philosophers, or, worse yet, drab realists. But we became none of these things. We kept our balance. We kept our feet on the ground when dreams filled our heads."

They reached the ship and stood before the opened outer valve.

The old man waved a hand toward the mighty metal building.

"The proudest city Man ever built," he said. "A city whose fame spread to the far stars, to distant galaxies. A city that travelers told about in bated whispers. A place to which came the commerce of many solar systems, ships from across far inter-galactic space. But now it is crumbling into dust and ruin. Soon the desert will claim it and the wind will sing a death dirge for it and little, furry animals will burrow in its bones."

He turned to them and Gary saw a half-mystic light shining in his eyes.

"Thus it is with cities," he said, "but Man is different. Man marches on and on. He outgrows cities and builds others. He outgrows planets. He is creating a heritage, a mighty heritage that in time will make him the master of the universe.

"But there will be interludes of defeat. Times when it seems that all is lost — that Man will slip again to the primal savagery and ignorance. Times when the way seems too hard and the price too great to pay. But always there will be bugles in the sky and a challenge on the horizon and the bright beckoning of ideals far away. And Man will go ahead, to greater triumphs, always pushing back the frontiers, always moving up and outward."

The old man turned around and headed back toward the doorway in the building. He went without a word of farewell and his sandaled feet left a tiny, ragged trail across the shifting sand.

CHAPTER Thirteen

THE black tunnel of the space-time wheel ended and the ship was in normal space again. Normal, but not right.

Gary, hunched over the controls, heard Caroline's quick gasp of surprise.

"There's something wrong!" she cried.

There was a world, but it was not the planet of the Engineers. No great city grew upon it from horizon to horizon. Instead of three blue suns, there was one and it was very large and red, a dull brick red, and its rays were so feeble that one could stare straight into it and at the edges it seemed that one could see straight through the fringe of gases.

There was no Hellhounds fleet, no flashing ships of the defender… no war.

There was peace upon this world… a quiet and deadly peace. The peace, thought Gary, of the never-was, the peace of all-is-over.

It was a flat splotched world with a leprous look about it, not gray, but colored as a child with water paints might color a paint book page when he was tired and all the need of accuracy and art were things to be forgotten.

Something happened, Gary told himself. And he felt the chill of fear in his veins.

Something happened and here we are — in what strange corner of the universe?

"Something went wrong," Caroline said again. "Some inherent weakness in the co-ordinates, some streak of instability in the mathematics themselves, perhaps."

"More likely," Gary told her, "the fault lies in the human brain — or in the brain of the Engineer. No man, no being, can see far enough ahead, think so clearly that be will foresee each eventuality. And even if he did, be might be inclined to let some small factor slip by with no other thought than that it was so small it could do no harm."

Caroline nodded at him. "The mistakes creep in so easy," she admitted. "Like mice… mice running in the mind."

"We can turn around and go back," said Gary, but even as he said it he knew that it was no good. For if the tunnel of distorted time-space through which they had come was jiggered out of position at this end, it would be out of focus at the other end as well.