It had been a wild twelve hours since Tom Hunter's call to his brother from the Map Room in Sun Lake City. The Major had arrived first, still buttoning his shirt and wiping sleep from his eyes. Johnny and Greg came in on his heels. They had found Tom waiting for them, so excited he could hardly keep his words straight.

He told them what he had found, and they wondered why they had not thought of it from the first moment. "We knew there had to be an answer," Tom said, "some place Dad could have used for a hiding place, some place nobody would even think to look. Dad must have realized that he didn't have much time. When he saw his chance, he took it."

And it was pure, lucky chance. Tom showed them the section of the Map he had examined, with the pinpoint of light representing Roger Hunter's asteroid claim. Then the Map Control officer ... much more alert when he saw Major Briarton ... brought an armload of films up and loaded them into the projector. They stared at the screen, and saw the two pinpoints of light where one was now.

"What was the date of this?" the Major asked sharply.

"Two days before Dad died," Tom said. "There's quite a distance between them there ... but watch. One frame for every hour. Watch what happens."

He began running the film, the record taken from the Map itself, accurate as clockwork. The white dot was moving in toward the red dot at a forty-degree angle. For an instant it looked as though the two were colliding ... and then the distance between them began to widen again. Slowly, hour by hour, the white dot was moving away, off the screen altogether....

The Major looked up at Tom and slammed his fist on the chair-arm. "By the ten moons of Saturn...." he exploded, and then he was on his feet, shouting at the startled Map Control officer. "Get me Martinson down here, and fast. Call the port on a scrambled line and tell them to stand by with a ship on emergency call, with a crack interceptor pilot ready to go. Then get me the plotted orbits of every eccentric asteroid that's crossed Mars' orbit in the last two months. And double-A security on everything ... we don't want to let Tawney get wind of this...."

Later, while they waited, they went over it to make sure that nothing was missing. "No wonder we couldn't spot it," the Major said. "We were looking for an asteroid in a standard orbit in the Belt."

"But there wasn't any," Tom said. "Dad's rock was isolated, nowhere near any others. And we were so busy thinking of the thousands of rocks in normal orbits between Mars and Jupiter that we forgot that there are a few eccentric ones that just don't travel that way."

"Like this one." The Major stared at the screen. "A long, intersecting orbit. It must swing out almost to Jupiter's orbit at one end, and come clear in to intersect Earth's orbit at the other end...."

"Which means that it cuts right through the Asteroid Belt and on out again." Tom grinned. "Dad must have seen it coming ... must have thought it was on collision course for a while. But he also must have realized that if he could hide something on its surface as it came near, it would be carried clear out of the Belt altogether in a few days' time."

"And if we can follow it up and intercept it...." The Major was on his feet, talking rapidly into the telephone. Sleep was forgotten now, nothing mattered but pinpointing a tiny bit of rock speeding through space. Within an hour the asteroid had been identified, its eccentric orbit plotted. The coordinates were taped into the computers of the waiting Patrol ship, as the preparations for launching were made.

It could not be coincidence. Somewhere on the surface of that tiny planetoid racing in toward the Sun they knew they would find Roger Hunter's secret.

Below them, as they watched, the jagged surface of the asteroid drew closer.

It was not round ... it was far too tiny a bit of cosmic debris to have sufficient gravity to crush down rocks and round off ragged corners. It was roughly oblong in shape, and one side was sheer smooth rock surface. The other side was rough, bristling with jutting rock. More than anything else it looked like a ragged mountain top, broken off at the peak and hurled into space by an all-powerful hand.

Slowly the scout-ship moved closer, braking with its forward jets. The pilot was expert. Carefully and surely he aligned the ship with the rock in speed and direction. In the accelleration cot Tom could feel only an occasional gentle tug as the power cut on and off.

Then the Lieutenant said, "I think we can make a landing now, Major."

"Fine. Take a scooter down first, and carry a guy line."

They unstrapped, and changed into pressure suits. In the airlock they waited until the Lieutenant had touched the scooter down. Then Major Briarton nodded, and they clamped their belts to the guy line.

One by one they leaped down toward the rock.

From a few miles out in space, the job of searching the surface had not appeared difficult. From the rock itself, things looked very different. There was no way, from the surface, to scan large areas, and the surface was so rough that they had to take constant care not to damage their boots or rip holes in their suits. There were hundreds of crevices and caves, half concealed by the loose rock that crumbled under their feet as they moved.

They spread out from the scooter for an hour of fruitless searching. Tom spent most of the time pulling his boots free of surface cracks and picking his way over heaps of jagged rock. None of them got farther than a hundred yards from the starting place. None of them found anything remarkable.

"We could spend weeks covering it this way," Greg said when they met at the scooter again. "Why don't I take the scooter and criss-cross the whole surface at about fifty feet? If I spot anything, I'll yell."

It seemed like a good idea. Greg strapped himself into the scooter's saddle, straddling the fuel tanks, using the hand jet to guide himself as he lifted lightly off the surface. He disappeared over the horizon of rock, then reappeared as he moved over the surface and back.

Tom and Johnny waited with the Major. Twenty minutes later Greg brought the tiny craft back again. "It's no good," he said. "I've scanned the whole bright-side, came as close as I dared."

"No sign of anything?" Johnny said.

"Not a thing. The dark side looks like a sheer slab, from what my lights show. If we only had some idea what we were looking for...."

"Maybe you weren't close enough," Tom said. "Why not drop each of us off to take a quarter of the bright-side and work our way in?"

The others agreed. Tom waited until the Major and Johnny had been posted; then he hopped on the scooter behind Greg and dropped off almost at the line of darkness, where the sheer slab began. All of them had hoped that there might be a sign, something that Roger Hunter might have left to mark his cache, but if there was one none of them spotted it. Tom checked with the others by the radio in his helmet, and started moving back toward the center of the bright side.

An hour later he was only halfway to the center, and he was nearly exhausted. At a dozen different spots he thought he had found a promising cleft in the rock, a place where something might have been concealed ... but exploration of the clefts proved fruitless.

And now his confidence began to fail. Supposing he had been wrong? They knew the rock had passed very close to Roger Hunter's asteroid, the astronomical records proved that. But suppose Dad had not used it as his hiding place at all? He pulled himself around another jagged rock shelf, staring down at the rough asteroid surface beyond....

At the base of the rock shelf, something glinted in the sunlight. He leaped down, and thrust his hand into a small crevice in the rock. His hand closed on a small metal object.

It was a gun. It felt well balanced, familiar in his hand ... the revolver Dad had always carried in his gun case.

He had to let them know. He was just snapping the speaker switch when he heard a growl of static in his earphones, and then Greg's voice, high-pitched and excited. "Over here! I think I've found something!"

It took ten minutes of scrambling over the treacherous surface to reach Greg. Tom saw his brother tugging at a huge chunk of granite that was wedged into a crevice in the rock. Tom got there just as the Major and Johnny topped a rise on the other side and hurried down to them.

The rock gave way, rolling aside, and Greg reached down into the crevice. Tom leaned over to help him. Between them they lifted out the thing that had been wedged down beneath the boulder.

It was a metal cylinder, four feet long, two feet wide, and bluntly tapered at either end. In the sunlight it gleamed like polished silver, but they could see a hairline break in the metal encircling the center portion.

They had found Roger Hunter's bonanza.

In the cabin of the scout-ship they broke the cylinder open into two perfect halves. It came apart easily, a shell of paper-thin but remarkably strong metal, protecting the tightly packed contents.

There was no question what the cylinder was, even though there was nothing inside that looked even slightly familiar at first examination. There were several hundred very tiny thin discs of metal that fit on the spindle of a small instrument that was packed with them. There were spools of film, thin as tissue but amazingly strong. Examined against the light in the cabin, the film seemed to carry no image at all ... but there was another small machine that accepted the loose end of the film, and a series of lenses that glowed brightly with no apparent source of power. There was a thick block of shiny metal covered on one side with almost invisible scratches....

A time capsule, beyond doubt. A confusing treasure, at first glance, but the idea was perfectly clear. A hard shell of metal protecting the records collected inside....

Against what? A planetary explosion? Some sort of cosmic disaster that had blown a planet and its people into the fragments that now filled the Asteroid Belt?

At the bottom of the cylinder was a small tube of metal. They examined it carefully, trying to guess what it was supposed to be. At the bottom was a tiny stud. When they pressed it, the cylinder began to expand and unfold, layer upon layer of thin glistening metallic material that spread out into a sheet that stretched halfway across the cabin.

They stared down at it. The metal seemed to have a life of its own, glowing and glinting, focussing light into pinpoints on its surface.

It was a map.

At one side, a glowing ball with a fiery corona, an unmistakeable symbol that any intelligent creature in the universe that was able to perceive it at all would recognize as a star. Around it, in clearly marked orbits, ten planets. The third planet had a single satellite, the fourth two tiny ones. The sixth eleven. The seventh planet had ten, and was encircled by glowing rings.

But the fifth planet was broken into four parts.

Beyond the tenth planet there was nothing across a vast expanse of the map ... but at the far side was another star symbol, this one a double star with four planetary bodies.

They stared at the glowing map, speechless. There could be no mistaking the meaning of the thing that lay before them, marked in symbols that could mean only one thing to any intelligence that could recognize stars and planets.

But in the center of the sheet was another symbol. It lay halfway between the two Solar Systems, in the depths of interstellar space. It was a tiny picture, a silvery sliver of light, but it too was unmistakeable.

It could be nothing else but a Starship.

Later, as they talked, they saw that the map had told each of them, individually, the same thing. "They had a star-drive," Tom said. "Whatever kind of creatures they were, and whatever the disaster that threatened their planet, they had a star-drive to take them out of the Solar System to another star."

"But why leave a record?" Greg wanted to know. "If nobody was here to use it...."

"Maybe for the same reason that Earthmen bury time capsules with records of their civilization," Major Briarton said. "I'd guess that the records here will tell, when they have been studied and deciphered. Perhaps there was already some sign of intelligent life developing elsewhere in the Solar System. Perhaps they hoped that some of their own people would survive. But they had a star-drive, so some of them must have escaped. And with the record here...."

"We may be able to follow them," Greg said.

"If we can decipher the record," Johnny Coombs said. "But we don't have any clue to their language."

"Did you have any trouble understanding what the map had to say?" the Major said quietly.

"No...."

"I don't think the rest will be much more difficult. They were intelligent creatures. The record will be understandable, all right." He started to fold the map back into a tube again. "Maybe Roger Hunter tried to use the film projector. We'll never know. But he must have realized that he had discovered the secret of a star-drive. He realized that the United Nations were the ones to explore it and use it, and he gave his life to keep it out of the hands of Tawney and his men...."

"A pity," a cold voice said close behind them, "that he didn't succeed, after all."

They whirled. In the hatchway to the after-cabin, Merrill Tawney was standing, with a smile on his lips and a Markheim stunner trained directly on Major Briarton's chest.