"No," he told her. "No twin moons or waving foliage. I dreamed I was a member of the garrison. I went through a training drill. I know how to operate those big machines on the second level of the corridor, now. They're weapons. I know how to use them." Sandy's uneasiness visibly increased. "These black cubes are--lesson-givers. They're subliminal instructors. Pam is more sensitive to such stuff than the rest of us. It didn't affect me until I dozed. Then I found myself instructed by going through an experience in the form of a dream. These cubes contain records of experiences. You have those experiences. You dream them. You learn." Then he said abruptly, "I understand my recurrent dream now, I think. When I was eleven years old I had a cube like this. Don't ask me how it got into a Cro-Magnon cave! But I had it. One day it dropped and split into a million leaves of shiny stuff. One got away under my bed, close up under my pillow. When I slept I dreamed about a place with two moons and strange trees and--all the rest." Sandy said, groping, "Do you mean it was magnetized in some fashion, and when you slept you were affected by it so you dreamed something--predetermined?" "Exactly," said Burke grimly. "The predetermined thing in this particular cube is the way to operate those machines Holmes said were weapons." Then he said more grimly, "I think we're going to have to accept the idea that this cube is an instruction device to teach the garrison without their having to learn to read or write or think. They'd have only to dream." Sandy looked from him to the small black cube. "Then we can find out--" "I've found it out," said Burke. "I guessed before, but now I know. There is an Enemy this fortress was built to fight. There is a war that's lasted for thousands of years. The Enemy has spaceships and strange weapons and is absolutely implacable. It has to be found. And the signals from space were calls to the garrison of this fortress to come back and fight it. But there isn't any garrison any more. We answered instead. The Enemy comes from hundreds or thousands of light-years away, and he tries desperately to smash the defenses of this fortress and others, and when he succeeds there will be massacre and atrocity and death to celebrate his victory. He's on the way now. And when he comes--" Burke's voice grew harsh. "When he comes he won't stop with trying to smash this place. The people of Earth are the Enemy's enemies, too. Because the garrison was a garrison of men!" Chapter 8 "I don't believe it," said Holmes flatly. Burke shrugged. He found that he was tense all over, so he took some pains to appear wholly calm. "It isn't reasonable!" insisted Holmes. "It doesn't make sense!"