"But how did they get them in their heads? And why? Especially, why do they waste them on the hawks?"
Jen glanced at him somberly from the circle of Hugh's arm. "We don't know, exactly. But the hawks are the eyes and ears of the Korins. And from the time they used the first sun-stone we've had no hope of getting free from them."
The thing that had been buried in Trevor's subconscious since last night's questioning came suddenly to the surface.
"Thought-waves, that's it! Sure!" He leaned forward excitedly, and Jen told him frantically to lower his voice. "I'll be damned. They've been experimenting with sun-stones for years on Earth—ever since they were discovered, but the scientists never thought of...."
"Do they have the stones on Earth, too?" asked Jen, with loathing.
"No, no, only the ones that are brought from Mercury. Something about Mercury being so close to the Sun, overdose of solar radiation and the extremes of heat, cold, and pressure while the planet was being made, that formed that particular kind of crystal here. I guess that's why they're called sun-stones."
He shook his head. "So that's how they work it—direct mental communication between the Korins and the hawks, by means of the stones. Simple, too. Set them right in the skull, almost in contact with the brain, and you don't need all the complicated machines and senders and receivers they've been monkeying with in the labs for so long." He shivered. "I'll admit I don't like the idea, though. There's something repulsive about it."
Hugh said bitterly, "When they were only men, and convicts, we might have beaten them some day, even though they had all the weapons. But when they became the Korins—" He indicated the darkling alcoves of the cave. "This is the only freedom we can ever have now."
Looking at Hugh and Jen, Trevor felt a great welling-up of pity, for them, and for all these far-removed children of Earth who were now only hunted slaves to whom this burrow in the rock meant freedom. He thought with pure hatred of the Korins who hunted them, with the uncanny hawks that were their far-ranging eyes and ears and weapons. He wished he could hit them with....