Shaking, he peered into the trap. It had been well made--about twenty feet deep, with walls as straight and narrow as the sand would allow, and skillfully covered with brush. Planted in the bottom were three wicked-looking flint spears. Had he been a shade less quick in his reactions, he would have lost the hound and perhaps himself. He skinned his teeth in a wolf-grin and looked around. The owlie must have worked all night on it. Then he couldn't be far away--and he'd be very tired-- As if to answer his thoughts, a boulder crashed down from the nearer cliff wall. It was a monster, but a falling object on Mars has less than half the acceleration it does on Earth. Riordan scrambled aside as it boomed onto the place where he had been lying. "Come on!" he yelled, and plunged toward the cliff. For an instant a gray form loomed over the edge, hurled a spear at him. Riordan snapped a shot at it, and it vanished. The spear glanced off the tough fabric of his suit and he scrambled up a narrow ledge to the top of the precipice. The Martian was nowhere in sight, but a faint red trail led into the rugged hill country. _Winged him, by God!_ The hound was slower in negotiating the shale-covered trail; his own feet were bleeding when he came up. Riordan cursed him and they set out again. They followed the trail for a mile or two and then it ended. Riordan looked around the wilderness of trees and needles which blocked view in any direction. Obviously the owlie had backtracked and climbed up one of those rocks, from which he could take a flying leap to some other point. But which one? Sweat which he couldn't wipe off ran down the man's face and body. He itched intolerably, and his lungs were raw from gasping at his dole of air. But still he laughed in gusty delight. What a chase! What a chase! * * * * * Kreega lay in the shadow of a tall rock and shuddered with weariness. Beyond the shade, the sunlight danced in what to him was a blinding, intolerable dazzle, hot and cruel and life-hungry, hard and bright as the metal of the conquerors. It had been a mistake to spend priceless hours when he might have been resting working on that trap. It hadn't worked, and he might have known that it wouldn't. And now he was hungry, and thirst was like a wild beast in his mouth and throat, and still they followed him. They weren't far behind now. All this day they had been dogging him; he had never been more than half an hour ahead. No rest, no rest, a devil's hunt through a tormented wilderness of stone and sand, and now he could only wait for the battle with an iron burden of exhaustion laid on him. The wound in his side burned. It wasn't deep, but it had cost him blood and pain and the few minutes of catnapping he might have snatched. For a moment, the warrior Kreega was gone and a lonely, frightened infant sobbed in the desert silence. _Why can't they let me alone?_