It was empty. Suddenly he felt a touch on his shoulder. Behind him, a familiar voice said, "Hello, Twin."
At first glance they looked like carbon copies of each other, although they were no more identical than identical twins ever are. Greg stood a good two inches taller than Tom. His shoulders were broad, and there was a small gray scar over one eye that stood out in contrast to the healthy tanned color of his face. Tom was of slighter build, and wirier, his skin much more pale.
But they had the same dark hair, the same gray eyes, the same square, stubborn line to the jaw. They looked at each other for a moment without speaking. Then Greg grinned and clapped his brother on the shoulder.
"So you got here, finally," he said. "I was beginning to think I'd have to go out on the desert and find you."
"Oh, I got here, all right," Tom said. "I see you did too."
"Yes," Greg said heavily. "Can't argue with the major, you know."
"But what does he want?"
"How should I know? All he said was to get down here fast. And now he isn't even here himself."
"Is Dad on Mars?" Tom asked.