"Whether or not you've found the cure for the Silver Plague. It hasn't
been checked yet. It's still killing thousands on Earth."
"So. I wondered a lot about that. Well--the answer is yes, Ed. I know
the answer."
"The cure?"
"Yes. I worked it out, completely, with the aid of the Ancients'
library. They were studying it too, but they didn't have quite the
right angle. However, they were able to supply the missing data I
needed." Willard took from his pocket a small notebook. "I had
five years to work on it. So far, of course, it's theoretical, but
everything checks. It's the cure, all right."
Somehow Garth didn't feel much excitement. Five years ago, he thought,
that notebook would have saved Moira's life. Now--well, it would still
save life. It would save Earth. But--
He shrugged. "Two good reasons to get back to civilization. The cure,
and the secret of the power-source."
Willard nodded. "The Ancients died of the Silver Plague, indirectly.
They tried to escape by changing their bodies. The library told me
that."
"Their bodies? How?"
"Well--you've seen the robots in Chahnn and here. Originally they were
the servants of the Ancients."
"Intelligent?"
"No--not in the way you mean. They could be conditioned to perform
certain tasks, but usually they were controlled telepathically by the
Ancients, who wore specialized helmet-transmitters for the purpose.
The robots had radioatomic brains that reacted to telepathic commands.
Then when the Silver Plague struck, the Ancients tried to escape by
transplanting, not their physical brains, but their _minds_. I don't
quite know how it was done. But the thought-patterns, the individual
mental matrix, of each Ancient was somehow impressed on the radioatomic
brain of a robot. Their minds were put into the robots' brains--and
controlled the metal bodies. So they escaped the Plague. But they died
anyway. Human, intelligent minds can't be transplanted successfully
into artificial bodies that way. So--in a hundred years--they were
dead, all of them."
So that was the secret of the Ancients' disappearance from Ganymede.
They had taken new bodies--and those bodies had killed them through
their sheer alienage.
Willard crushed out his cigaret-stub. "All the knowledge of the
Ancients at my finger-tips, Ed. You can imagine what research I've
done!"
"I should have thought you'd have looked for a weapon against the
Zarno," Garth said practically. "The Ancients were able to conquer
them."
"I did--first of all, after I'd learned how to work the
recording-machines. A certain ray will destroy them--a vibrationary
beam that shakes them to pieces, disrupts their molecular structure.
The only trouble is--" Willard grinned sardonically. "It takes a damn
good machine shop to build such a projector."
"Oh. We couldn't--"
"We couldn't. The Ancients left plenty of apparatus here, but not the
right kind. Mostly records, and a lot of robots. Sorry, Ed, but unless
you brought good weapons with you, you're stuck here with me."
* * * * *
Garth looked around to where his companions were standing motionless.
"Yeah. Looks like it. Unless we can break through to that hangar of
antigravity ships--"
"We can't. The city's full of the Zarno, day and night. And there are
always guards outside."
Garth sighed. "The trouble is, unless we get out, nothing can stop the
Silver Plague. Not to mention the fuel shortage. Wait a minute. You
said the Zarno were superstitious--we tricked them once with a fake
ceremony. Couldn't we try that again?"
"I did," Willard told them. "It didn't work. The Zarno know what human
beings are like now. Only the gods would impress them--those robots who
once were their masters."
Garth stopped breathing for a moment.
"There's a way," he said.
Willard looked at him. "I don't think so. When I saw you'd come back, I
hoped for a minute--but it's no use. The Zarno are invulnerable to any
weapons we can create here. We can't get out of the city!"
"You said the gods would impress them."
"The gods are dead--the Ancients."
"Suppose one of them came back?"