Nolan frowned. Those mud-colored patches were water. Undoubtedly. A narrow-band light filter proved it. But the areas which were neither sea nor cloud mass? There were three levels of brightness to be seen on the disk outside the polar areas. One was sea-bottom. One was cloud. The other....

Nolan fretted a little. There was something wrong. The solid ground surface of the planet was too light in color. It was such items that a person with a knack for it would notice sooner than a man without the knack. Vegetation should be more nearly midway between sea-bottom and cloud mass in color.

Nolan fitted in the chlorophyll filter. On the planet of a sol-type sun, vegetation had to use chlorophyll or else. Through this filter the clouds would show, of course. They were white and reflected all colors of light. But no color that chlorophyll didn't reflect could pass through the filter.

The cloud masses showed clearly. Nothing else appeared. The filters would have shown vegetation. It didn't. It said there wasn't any.

Nolan stepped up the magnification. He saw other things. He didn't like them. He got some maximum-magnification pictures and interpreted them with increasing grimness.

He went to make his report just as the system constants began to reach the skipper. The local sun's mass was 1.3 sols. The solar rotation period was thirty-four days. There were sunspots of perfectly familiar kinds. The Lauriac Laws about the size and distribution of planets in a sol-type system were borne out. One was small, and its sunward side was probably at a low red heat. This was like Mercury. Planet Two, like its analogue Venus in the home system, would be resolutely unoccupiable by man. Planet Four—analogous to Mars—was smaller than Three and had a very thin atmosphere. There were gas-giants in orbits six and seven. Then a novelty Lauriac's laws predicted things about fifth planets, too, but they'd never been verified because fifth planets were unstable. They blew up. Only fragments—asteroids—had so far been noted where fifth planets of sol-type suns ought to be. But there was a fifth planet here, rolling magnificently through emptiness. It matched the Lauriac predictions. It had an atmosphere, which should contain oxygen. It was the first sol-system fifth planet ever observed.

There was a babble in the skipper's office as the discoverers of the fifth planet told him about it.

Nolan said curtly, "I've something more urgent to report. Planet Three ought to be like Earth. It was. It isn't, any longer. It's dead!"

Nobody paid attention. There was a fifth planet! It was unparalleled! All the theories about the absence of fifth planets could now be checked!

"I'm telling you," said Nolan sharply, "that the third planet's dead! It was alive, and something happened to it! It has seas and clouds and ice-caps, and they're water! But its land surface is pure desert! Where life can exist, it does. Always! Life did exist here. Now it doesn't." He turned to the skipper, "Maybe bug-eyed monsters killed it, skipper. It looks to me like murder!"

Then they stared at him. He spread out his pictures. He pointed out this item and that. They were conclusive. Nobody else might have realized the facts behind them quite so soon, but when put together they fitted.

"Familiar, eh?" asked Nolan sardonically. "You recognize the pictures like them before. They weren't made with cameras, like these, but artists drew them from descriptions of what would happen. Here it's happened! I think," he added, looking at the skipper, "that this is more important than fifth planets. I think we'd better go over and get what information we can and take it home. Death like this implies life a lot like men. If non-human creatures can do something as human as this, we'd better get the word back home so something can be done to get ready before we find them—or they find us."

The skipper went carefully over the pictures. On one he put his finger on a feature Nolan hadn't mentioned. He seemed to wince.

"I think you win, Nolan," he said painfully. "We'll send a drone down. I doubt we can land, but this ought to be checked. Immediately. Maybe I should add—inconspicuously."

"I think," said Nolan, "that I make a landing. Right?"

The skipper said crossly, "Yes. You're the best man for it. You notice things. But I doubt you'll learn very much." He tapped the written report that the radiation background count was 3.9. "It happened a long time ago. A long, long time ago!" Then he said with a totally unsuccessful attempt at humor, "Try and find out that it was bug-eyed monsters, eh? It looks too much like Earth! I'd rather blame monsters than men!"

Nolan growled and went to prepare for the landing. Two other men would go with him, of course. The Lotus wouldn't descend. It cost fuel to make landings. Unless there was some remarkable specimen that a drone couldn't handle the ship would stay aloft.

So a drone took three of them down to ground, a second drone following with equipment. They had weapons, of course. Men never land anywhere without weapons. They had the material for a foam-house camp. They had a roller-jeep, running on huge inflated bags. It would run efficiently on anything from sand to swamp mud, and float itself across bogs or rivers. They had cameras and communicators. Nolan had picked Crawford for geology and Kelley for communications. They could get other specialists from the ship, if desirable.

The ground where they landed was desert: nothing more. There were enormous dunes like gigantic frozen swells of sand. Sometimes there were miles between crests. They landed close to the mud banks northern ice-cap to avoid the deep gorges in which rivers ran farther south. On the first day they set up their camp.

Mountains reared to the north of them, covered almost to their bases with ice. These they need not explore. Instruments would do most of the landing-party work, in any case. But they inflated small balloons and sent them skyward, to learn about currents of the upper air, and Crawford took painstaking photographs of dune formations, and they set up a weather radar. They checked the water recovery from the camp's air-conditioner. It would supply their needs. When night drew near, with all instruments recording, they watched the sunset.

At long last the skipper nodded permission for Nolan to try the eyepiece, to see what it showed with heavy metal and much soil and vegetation atop it. They taped the trigger so it could not be moved. The controls affecting the eyepiece they left free. The skipper almost dripped sweat as Nolan turned on the eyepiece circuit, peering in.

For a long time he saw nothing whatever. Then a tiny disk moved slowly into the eyepiece's field. It was barely larger than a point. Nolan moved one of the eyepiece controls. The disk enlarged. It enlarged again. A tiny red dot appeared in the center of the field of vision. As the disk enlarged, the red dot grew larger and became a tiny red circle.

Nolan fumbled. He shifted the position of the instrument with a micro-control. He moved the faintly glowing disk until it was enclosed in the red circle. He enlarged.... Presently the disk was very large, and the red circle ceased to enlarge. It enclosed only a part of the disk.

Nolan felt cold chills down his spine. He swallowed and asked for the angular relationship of Planet Four to Three. The skipper sent someone to find it out. But Nolan had found Planet Four before the answer came. The first disk was in some fashion a representation of Planet Three—the Earthlike world which was dead. The second was a representation of Four. There was a bright spot near the equator of Four—the equator being located by the flattening of the poles. It would be just about where a gigantic atom-bomb crater still existed.

Nolan drew back and took a deep breath.

"Apparently," he said unsteadily, "this eyepiece detects radioactives, converting something that I can't imagine into visible light after it's passed through a few feet of metal and a good many more of dirt. There's a red ring which makes me think of a gun-sight. And there's a trigger. Skipper, would you send half an ounce or so of ship-fuel out to space in a drone? I think we're going to have to pull this trigger."

The skipper wrung his hands. He went away. And Nolan stood staring at nothing in particular, appalled and sickened by the thoughts that came to him.

Presently the skipper came back and mumbled that a drone was on the way up. Nolan searched for it with the eyepiece. He found it. The sensitivity of the eyepiece was practically beyond belief. What it worked on—what it transmuted and amplified to light—was wholly beyond his imagination.

The drone went four thousand miles out. Nolan absently asked for somebody to be posted out of doors, watching the sky. He got the vivid spark that was the half ounce of ship-fuel in the center of the red luminous ring. He turned his eyes away and pulled the trigger.

There was no sound. There was no vibration. There was no indication in the underground room that anything at all had happened. There was only a violent flare in the eyepiece, from which Nolan had just drawn back.

Three Com rockets reached their targets, and Nolan never quite forgave himself for it. They were murderous. They wiped out cities. But that was all. The rest of the rockets went off prematurely. A spread of half a hundred, crossing the North Pole, detonated just out of atmosphere. Others went off over the Atlantic. Not a few made temporary suns above the Pacific. Nolan brought moving specks within the thin red circle of his instrument, and pulled the trigger. The points flamed momentarily and left patches of luminosity behind them. And that was that.

But they continued to rise. On Earth they made noises like dragons. There was panic from their starting points. Those first out had not reached their targets! So the Com launching-sites flung more and more missiles skyward. One of them reached a city of the West. A second. A third.

The only possible answer was to blast them as they rose. Then to blast them before they rose. Nolan's task became the terribly necessary one of preventing radioactives from moving away from Com territory and into WDA nations—specifically one WDA nation. He did not think of the consequences of his actions except in terms of preventing excessively bright mathematical points of light from getting to the areas where there were so many fewer points of similar light which did not move at all. He tried to stop only those that moved.

But three got by him, and he could do nothing but detonate all the radioactives in Com territory. He had to! When that was done, there were six warheads coming up from Earth. He detonated them. There were massed warheads moving toward Earth from the Moon. It seemed that they practically tore space apart that they went off together. Then the moon base began to fire rockets, hysterically, at the Lotus, and it was necessary to detonate the radioactives in the moon base.

It had been estimated that an atomic war might be over in three hours. But prophecies are usually underestimates. Between the first and last explosions on Earth, in space and on the moon—there was a truly gigantic crater where the Com base had been—some thirty-seven minutes elapsed. Then the war was over.

There were some survivors in Com territory, of course. But they couldn't retaliate for the destruction of their nations. Their own bombs had done the destruction. They couldn't even gloat that the rest of Earth shared their catastrophe. It didn't. Most of the bombs exploded high, and over ocean. No less than three-fifths of all fallout landed in the sea and sank immediately. For the rest, the background count on Earth nowhere went above 4.9, and people could be protected against that.

The survey ship Lotus came gingerly down to ground. There was no longer any reason for tension. Its crew reported in and scattered to the various places they called home. They were very glad to be back. In the course of time they were all suitably bemedalled and admired and told that their names would live forever. Of course, it was not true.

Nolan didn't pay much attention to this. He left the Survey. He went to live in a small town. He married a small-town girl. And he never, never, never took any one of the excursions so many WDA people took to see the result of atomic explosions in Com territory, when their attempt to murder one Western nation backfired. Nolan had caused that backfiring. He very passionately did not want to see its results.

He'd seen all he wanted of that sort of thing on the third planet of a sol-type sun, some light-centuries from Earth.