"It doesn't make sense the way we've been looking at it," Tom said. "All
we've found was some gobbledegook in Dad's private log to tell us what
he found ... but it couldn't have been a vein of ore, or Tawney's men
would have unearthed it. It had to be something else. Something that was
so big and important that Dad didn't even dare let Johnny in on it."

"Yes, that's been the craziest part of it, to me," Johnny said. "I've
done a lot of mining with your Dad. If he'd hit rich ore, he would have
taken me out there to mine it with him. But he didn't. He said it was
something he had to work on alone for a while, and he sent me back."

"As if he'd found something that scared him," Tom said, "or something
that he didn't understand. He was _afraid_ to tell anybody. And whatever
he found, he managed to hide it somewhere, so that nobody would find
it...."

"Then why didn't he hide this part of it, too?" Greg said.

"Maybe to be sure there was some trace left, if anything happened to
him," Tom said.

They were silent for a moment. The only sound was the stertorous
breathing of the unconscious guard. "Well," Greg said finally, "I have
to admit it makes sense. It makes other things add up better, too. Dad
was no fool, he must have known that Tawney was onto something. And Dad
would never have risked his life for an ore strike. He'd either have
made a deal with Tawney or let him hijack the lode, if that was all
there was to it. But there's still one big question ... where did he
hide what he found? And we aren't going to find the answer here." He
walked over to the hole in the wall.

"Made quite a mess of it, didn't it?" Johnny said.

"Looks like it. I wonder what that thing would do to a ship's generator
plant." He turned to Johnny. "We haven't much time. With this thing, we
could tear this ship apart, leave them so confused they'll never know
what broke loose. And if we could get that gun back to Major Briarton,
he'd have to listen to us, and get the U.N. Patrol into the search...."

They had been so intent on their talking that they did not hear the
footsteps in the corridor until the door swung open. It was another
guard, the one who had departed with Tawney. He stopped short, blinking
at his companion on the floor, and then at the gaping hole in the wall.
When he saw the twins, side by side, his jaw sagged and a strangled
sound came from his throat.

Then Johnny grabbed his arm, jerked him into the lounge, and slamme