"Can't prove it wasn't."

"But at least you've got some ideas," Tom said.

"Takes more than ideas to make a case," he said at length. "But there's one thing I do know. I've got no proof, not a shred of it, but I'm sure of one thing just as sure as I'm on Mars." He looked at the twins thoughtfully. "Your dad wasn't just prospecting, out in the Belt. He'd run onto something out there, something big."

The twins looked at him. "Run onto something?" Greg said. "You mean...."

"I mean I think your dad hit a Big Strike out there, rich metal, a real bonanza lode. Maybe the biggest strike that's ever been made," the miner said slowly. "And then somebody got to him before he could bring it in."

3. Too Many Warnings

For a moment, neither of the boys could say anything at all.

From the time they had learned to talk, they had heard stories and tales that the miners and prospectors told about the Big Strike, the pot of gold at the end of the rainbow, the wonderful, elusive goal of every man who had ever taken a ship into the Asteroid Belt.

For almost a hundred and fifty years ... since the earliest days of s.p.a.ce exploration ... there had been miners prospecting in the Asteroids. Out there, beyond the orbit of Mars and inside the orbit of Jupiter, were a hundred thousand ... maybe a hundred million, for all anybody knew ... chunks of rock, metal and debris, spinning in silent orbit around the sun. Some few of the Asteroids were big enough to be called planets ... Ceres, five hundred miles in diameter; Juno, Vesta, Pallas, half a dozen more. A few hundred others, ranging in size from ten to a hundred miles in diameter, had been charted and followed in their orbits by the observatories, first from Earth's airless Moon, then from Mars. There were tens of thousands more that had never been charted. Together they made up the Asteroid Belt, spread out in s.p.a.ce like a broad road around the sun, echoing the age-old call of the bonanza.

For there was wealth in the Asteroids ... wealth beyond a man's wildest dreams ... if only he could find it.

Earth, with its depleted iron ranges, its exhausted tin and copper mines, and its burgeoning population, was hungry for metal. Earth needed steel, tin, nickel, and zinc; more than anything, Earth needed ruthenium, the rare-earth catalyst that made the huge solar energy converters possible.

Mars was rich in the ores of these metals ... but the ores were buried deep in the ground. The cost of mining them, and of lifting the heavy ore from Mars' gravitational field and carrying it to Earth was prohibitive. Only the finest carbon steel, and the radioactive metals, smelted and purified on Mars and transported to Earth, could be made profitable.

But from the Asteroid Belt, it was a different story. There was no gravity to fight on the tiny asteroids. On these chunks of debris, the metals lay close to the surface, easy to mine. Ships...o...b..ting in the Belt could fill their holds with their precious metal cargoes and transfer them in s.p.a.ce to the interplanetary orbit-ships spinning back toward Earth. It was hard work, and dangerous work; most of the ore was low-grade, and brought little return. But always there was the lure of the Big Strike, the lode of almost-pure metal that could bring a fortune back to the man who found it.

A few such strikes had been made. Forty years before a single claim had brought its owner seventeen million dollars in two years. A dozen other men had stumbled onto fortunes in the Belt ... but such metal-rich fragments were grains of sand in a mighty river. For every man who found one, a thousand others spent years looking and then perished in the fruitless search.

And now Johnny Coombs was telling them that their father had been one of that incredible few.

"You really think Dad hit a bonanza lode out there?"

"That's what I said."

"Did you see it with your own eyes?"

"No."

"You weren't even out there with him!"

"No."

"Then why are you so sure he found something?"

"Because he told me so," Johnny Coombs said quietly.

The boys looked at each other. "He actually _said_ he'd found a rich lode?" Tom asked eagerly.

"Not exactly," Johnny said. "Matter of fact, he never actually told me _what_ he'd found. He needed somebody to sign aboard the _Scavenger_ with him in order to get a clearance to blast off, but he never did plan to take me out there with him. 'I can't take you now, Johnny,' he told me. 'I've found something out there, but I've got to work it alone for a while.' I asked him what he'd found, and he just gave me that funny little grin of his and said, 'Never mind what it is, it's big enough for both of us. You just keep your mouth shut, and you'll find out soon enough.' And then he wouldn't say another word until we were homing in on the shuttle ship to drop me off."

Johnny finished his coffee and pushed the cup aside. "I knew he wasn't joking. He was excited, and I think he was scared, too. Just before I left him, he said, 'There's one other thing, Johnny. Things might not work out quite the way I figure them, and if they don't ... make sure the twins know what I've told you.' I told him I would, and headed back.

That was the last I heard from him until the Patrol ship found him floating in s.p.a.ce with a torn-open suit and a ruined scooter floating a few miles away."

"Do you think that Jupiter Equilateral knew Dad had found something?"

Tom asked.

"Who knows? I'm sure that _he_ never told them, but it's awful hard to keep a secret like that, and they sound awful eager to buy that rig,"

Johnny Coombs said.

"Yes, and it doesn't make sense. I mean, if they were responsible for Dad's accident, why didn't they just check in for him on schedule and then quietly bring in their rig to jump the claim?"

"Maybe they couldn't find it," Johnny said. "If they'd killed your dad, they wouldn't have dared hang around very long right then. Even if they'd kept the signal going, a Patrol ship might have come into the region any time. And if a U.N. Patrol ship ever caught them working a dead man's claim without reporting the dead man, the suit would really start to leak." Johnny shook his head. "Remember, your Dad had a dozen claims out there. They might have had to scout the whole works to find the right one. Much easier to do it out in the open, with your signatures on a claim transfer. But one thing is sure ... if they _knew_ what Roger found out there, and where it was, Tawney would never be offering you triple price for the rig."

"Then whatever Dad found is still out there," Tom said.

"I'd bet my last dime on it."

"There might even be something to show that the accident wasn't an accident," Tom went on. "Something even the Major would have to admit was evidence."

Johnny Coombs pursed his lips, looking up at Tom. "Might be," he conceded.

"Well, what are we waiting for? We turned Tawney's offer down ... he might be sending a crew out to jump the claim right now."

"If he hasn't already," Johnny said.

"Then we've got to get out there."

Johnny turned to Greg. "You could pilot us out and handle the navigation, and as for Tom...."

"As for Tom, he could get sick all over the place and keep us busy just taking care of him," Greg said sourly. "You and me, yes. Not Tom. You don't know that boy in a s.p.a.ceship."

Tom started to his feet, glaring at his brother. "That's got nothing to do with it...."

"It's true, isn't it? You'd be a big help out there."

Johnny looked at Tom. "You always get sick in free fall?"

"Look, let's be reasonable," Greg said. "You'd just be in the way. There are plenty of things you could do right here, and Johnny and I could handle the rig alone...."

Tom faced his brother angrily. "If you think I'm going to stay here and keep myself company, you're crazy," he said. "This is one show you're not going to run, so just quit trying. If you go out there, I go."

Greg shrugged. "Okay, Twin. It's your stomach, not mine."

"Then let me worry about it."