"Oh, they are diabolic, these Specials of Vaajo's! They have machines which tear a man's mind apart, probe into his inner thoughts. No spy could ever get past them." "Then how do _you_ propose to get by, O grinning one?" The black continued to grin. "True," he said frankly, "I am _S'Relah_. And there are several others among us. We shall get by the Specials all right, and into Turibek by the main gate. For the past year we have prepared for this, through systematic thought-control. We can submerge our true thoughts so that all the machines will read will be obeisance and loyalty." "Seems ticklish," Ketrik said. "But I guess I'll try that too." He had no intention of trying it. He was watching Aarnto's reaction. "Listen to me." Aarnto was serious, gripping Ketrik's arm. "You could never manage it. It takes months to perfect such mind control, and you have only hours. I do not know why you wish to get to Turibek, but you quoted the oath to me. I know of another way into the city for you--it will be perilous but not so perilous as trying to run the gauntlet of Specials!" "I am listening, O helpful one." "We will reach this station before sundown. If you should leave the caravan now, and cut across desert to the foothills, you would be safe. Once over there...." Now it was Ketrik who grinned. "I know. Once over there, I might find the entrance to the ancient South Canal." Aarnto was amazed. "You know of that too?" "I've heard of it, but don't know the exact location." Aarnto pointed to the K'Mari Range, indicating twin peaks that curled up like devil's horns. "Guide your course directly between those. The Canal ends somewhere in the foothills below." "Thanks, Aarnto." Ketrik placed his hand on the man's shoulder, in the Rajec custom. "May I repay you some day!" "That day may come soon," the other said calmly. "I can almost promise it." Ketrik wondered what he meant by that, but wasted no more time on words. Turning abruptly, he set out across the desert. The six Martians watched him go. One of them, who had been silent and surly, frowned thoughtfully now as he stared after Ketrik's retreating figure. Ketrik judged the hills to be fifteen miles away at this point. He'd be lucky if he reached them before nightfall. After that, well, there were tales about those abandoned Canals.... He directed his course between the curving peaks. In a few hours the ground began to rise slightly, became firmer underfoot. Still later, deep little gullies began crossing the terrain. He followed these, changing from one to the other, searching for some sign of the Canal. After an interminable search, he was rewarded. He began to notice peculiarities of the gully in which he trod. It seemed to level out, and the walls seemed smoother and higher. He scraped away layers of sand, saw ancient stone.