"Shut up," the bald man said. * * * * * All day the bald man had been out alone, working on his electronic circuits. Evidently this left his partner nothing to do except study schematics. Now Martin Devere was aware that his guest had been staring at him for several minutes without speaking. Martin Devere went on polishing the green crystal vase he held in his hand. The vase looked ordinary at first glance, until you noticed that it wasn't quite symmetrical. There was a studied and careful asymmetry about its form, barely discernible, that would disturb you the more you looked at it--until you knew suddenly that no human brain could have created that shape. The polishing cloth moved rhythmically across the vase's curving surfaces. The green crystal reflected light in a way that made you begin to think about boundless seas of water. "I'll be glad when this job is over with," the tall man said, half aloud. "When it is, will you go away?" Martin Devere turned the vase slowly in his hands. "Not for a while yet, Pop." The man with the gun on his hip got to his feet and stretched. "I don't mind telling you what it's all about, Pop. You're all right. It's simple. My partner and I were sent here by a certain national power that doesn't like being told how to run its own affairs by the United Governments. We're striking the first blow for Freedom. That thing we're putting together out there is a bomb. It could--disable--most of Earth. It has a new kind of nuclear rocket engine behind it that could carry it across 200 million miles in a few hours. "You get the idea, Pop? Here on Mars, they won't even find it. And if they did, we could deliver the bomb before they got a missile halfway across.... So I hope you won't mind if my partner and I stay a while, Pop." It was several seconds before Martin Devere answered. He set the crystal vase carefully inside a case and regarded it a moment. "As long as you don't go messing up my diggings or break any of the artifacts, it's no business of mine." "And what if I did, Pop?" The tall man walked closer to Martin Devere. He stood over the old man, his shadow on him. His hand rested lightly on the butt of his gun. "What if I were to take all your vases and statues and pots and tablets and smash them to bits, one by one? What would you do then?" Martin Devere's eyes slowly closed and opened, he made no other move for a minute. Then he got to his feet without looking at the other man. He turned and began to move away, toward a tunnel door that led to the diggings. Probably the tall man thought that he had finally put the fear of God into Martin Devere. But as he turned back to his pile of schematics he heard the old man's whisper: "You might regret it." The man with the gun did not answer. * * * * * "Tell us about it, Pop." "Yes, why don't you tell us about it."