"Yes, there is air here," said the Martian leader, startlingly. "Not enough for your use, however, so do not open your helmets." Syme swore amazedly. "I thought you said they didn't speak Terrestrial," Tate said. Syme ignored him. "We had our reasons for not doing so," the Martian said. "But how--?" "We are telepaths, of course. On a planet which is nearly airless on its surface, we have to be. A tendency of the Terrestrial mind is to ignore the obvious. We have not had a spoken language of our own for several thousand years." He darted a glance at Syme's darkly scowling face. His own hairy face was expressionless, but Syme sensed that he was amused. "Yes, you're right," he said. "The language you and your fellows struggled to learn is a fraud, a hodge-podge concocted to deceive you." Tate looked interested. "But why this--this gigantic masquerade?" "You had nothing to give us," the Martian said simply. Tate frowned, then flushed. "You mean you avoided revealing yourselves because you--had nothing to gain from mental intercourse with us?" "Yes." Tate thought again. "But--" "No," the Martian interrupted him, "revealing the extent of our civilization would have spared us nothing at your people's hands. Yours is an imperialist culture, and you would have had Mars, whether you thought you were taking it from equals or not." "Never mind that," Syme broke in impatiently. "What do you want with us?" The Martian looked at him appraisingly. "You already suspect. Unfortunately, you must die." * * * * * It was a weird situation, Syme thought. His mind was racing, but as yet he could see no way out. He began to wonder, if he did, could he keep the Martians from knowing about it? Then he realized that the Martian must have received that thought, too, and he was enraged. He stood, holding himself in check with an effort. "Will you tell us why?" Tate asked. "You were brought here for that purpose. It is part of our conception of justice. I will tell you and your--friend--anything you wish to know." Syme noticed that the other Martians had retired to the farther side of the cavern. Some were munching the glowing fungus. That left only the leader, who was standing alertly on all fours a short distance away from them, holding the Benson gun trained on them. Syme tried not to think about the gun, especially about making a grab for it. It was like trying not to think of the word "hippopotamus." Tate squatted down comfortably on the floor of the cavern, apparently unconcerned, but his hands were trembling slightly. "First why--" he began. "There are many secrets in Kal-Jmar," the Martian said, "among them a very simple catalyzing agent which could within fifty years transform Mars to a planet with Terrestrially-thick atmosphere."