"Hell," enthused Herb, "I bet the Engineers could tell us how to make that fuel. These boys are bell-ringers all around."

"If there is any way we can help you, anything you want, anything at all," declared the Engineer, "we would be so glad, so proud to help you."

"I bet you would at that," said Herb.

"Only a few of the denizens we called have arrived," said the Engineer. "More of them should have come. Others may be on their way. We are afraid…"

He must have decided not to say what was on his mind, for thought clicked off, broken in the middle of the sentence.

"Afraid?" asked Kingsley. "Afraid of what?"

"Funny," said Gary, almost to himself. "Funny they should be afraid of anything."

"Not afraid for ourselves," explained the Engineer. "Afraid that we may be forced to halt our work. Afraid of an interruption. Afraid someone will interfere."

"But who would interfere?" asked Caroline. "Who could possibly interfere in a thing like this? The danger is a common one. All things within the universe should unite to try to fight it."

"What you say is right," declared the Engineer. "So right that it seems impossible any could think otherwise. But there are some who do. A race so blinded by ambition and by hatred that they see in this approaching Catastrophe an opportunity to wipe us out, to destroy the Engineers."

The Earthlings stood stock-still, shocked.

"Now, wait a second," said Gary slowly. "Let us understand this. You mean to say that you have enemies who would die themselves just for the satisfaction of knowing that you were destroyed, too?"

"Not exactly," said the Engineer. "Many of them would be destroyed, but a select few would survive. They would go back to the point where the universe must start again, back to the point where space and time would once more begin expanding. And, starting there, they would take over the new universe. They would shape it to fit their needs. They would control it. They would have complete dominion over it."

"But," cried Gary, "that is mad! Utterly mad. Sacrificing a present people, throwing away an entire universe for a future possibility."

"Not so mad," said Kingsley quietly. "Our own Earth history will furnish many parallels. Mad rulers, power-mad dictators ready to throw away everything for the bare feel of power… ready to gamble with the horrors of increasingly scientific and ruthless warfare. It almost happened on Earth once… back in 2896. The Earth was almost wiped out when one man yearned for power and used biological warfare in its most hideous form. He knew what the result would be, but that didn't stop him… Better, he reasoned, if there were no more than a thousand persons left alive, if he were the leader of that thousand. Nothing stopped him. The people themselves later stopped him, after he had done the damage… stopped him like the mad dog that he was."

"They hate us," said the Engineer. "They have hated us for almost a million years. Because we, and we alone, have stood between them and their dreams of universal conquest. They see us as the one barrier they must remove, the one obstacle in their way. They know they never can defeat us by the power of arms alone, cannot defeat us so utterly that we still cannot smash their plans to take over the universe."

"And so," said Gary, "they are perfectly willing to let the collision of universes wipe you out, even if it does mean disaster and destruction for the most of them."

"They must be nuts," said Herb.

"You do not understand," protested the Engineer. "For many millions of years they have been educated with the dream of universal conquest. They have been so thoroughly propagandized with the philosophy that the state, the civilization, the race, is everything… that the individual does not count at all… that there is not a single one of them who would not die to achieve that dream. They glory in dying, glory in any sort of sacrifice that advances them even the slightest step toward their eventual goal."

"You said that some of them would survive even if the universe, as we know it, were destroyed," said Caroline. "How would they do that?"

"They have found a way to burst out of the universe," said the Engineer. "How to navigate the inter-space that exists outside the universe. They are more advanced in many sciences that we. If they wished, I have no doubt they could by themselves, with no aid at all, save us from the fate that is approaching."

"Perhaps," rumbled Kingsley, "a treaty could be arranged. A sort of eleventh-hour armistice."

The impersonal thought of the Engineer struck at them. "There can be no peace with them. No treaty. No armistice. For more than a million years they have thought and practiced war. Their every thought has been directed toward conquest. To them the very word «peace» is meaningless. War is their natural state, peace an unnatural state. And they would not, in any event, in the remote chance that they might consider an armistice, consider it at this time when they have a chance to prevent us from saving the universe."

"You mean," asked Gary, horror in his voice, "that they actually want the universe destroyed? That they would fight you to prevent you from saving it?"

"That," said the Engineer, "is exactly what I mean. You understand so well."

"Do you expect them to attack soon?" asked Tommy.

"We do not know. They may attack at any time. We are ready at all times. We know they will attack eventually."

"We must find a way," said Caroline. "We can't let them stop us! We must find a way!"

"We will find a way," rumbled Kingsley. "There has to be a way, and we'll find it."

"What do you call these rip-snorters you've been fighting all these years?" asked Herb.

"We call them the Hellhounds," said the Engineer, but that was not exactly what he meant. The thought brought together a certain measure of loathing mixed with fear and hatred. Hellhounds was the nearest the Earthlings could translate the thought.

"They can break through the time-space curve," said Caroline, musingly, "and they can travel in the fifth-dimensional inter-space." She flashed a look at Gary, a look filled with the flare of inspiration. "Perhaps," she said, "that is the answer. Perhaps that is what we should try to find the answer to."

"I don't know what you mean," said Gary, "but maybe you are right."

"The space-time curve would be rigid," said Kingsley. "Rigid and hard to unravel. Lines of stress and force that would be entirely new. That would take mathematical knowledge. That and tremendous power."

"The power of new energy," said Gary. "Perhaps the power of the energy the rubbing universes will create."

Kingsley stared at him as if he had struck him with an open hand. "You have it," he shouted. "You have it!"

"But we haven't got the energy," said Gary, bluntly.

"No," agreed Kingsley. "We'll have to get that first."

"And control it," said Caroline.

"Perhaps," suggested the Engineer, "we should go now. The others are waiting for us. They have come so far, many of them from greater distances than you."

"How many are there?" asked Gary.

"Only a few," said the Engineer, "so very few. Life is so seldom found throughout the universe. The universe does not care for life. I sometimes think life is merely a strange disease that should not be here at all, that it is some accidental arrangement of matter that has no right to be. The universe is so hostile to it that it would seem almost to be abnormal. There are so few places where it can take root and live."

"But throughout those billions of galaxies there must be many races," declared Kingsley.

"There may be many we do not know about," said the Engineer, "but very few that we can contact. It is so very hard to get in touch with them. And some of them would be useless to us, races that had developed along entirely different lines to achieve a different culture. Races that live without the application of any of the practical sciences. Races that are sunken in the welter of philosophy and thought. Races that have submerged themselves in aesthetics and are untrained in science. The only ones we could reach were those scientifically-minded races that could catch our message and could reply to us… and after that could build the apparatus that would bring them here."