Crag raised his gun, wondering if he could hold the man in his sights. A hundred and fifty yards to a rifleman clothed in a cumbersome space suit seemed a long way. Before he could pull the trigger, the man flung his arms outward, clawing at his throat for an instant before slumping to the rocks. It took Crag a second to comprehend what had happened. Prochaska had been ready. A figure suddenly filled the dark rectangle of Bandit, pointing toward the ridge behind Crag. He apparently was trying to tell him something. Crag scanned the ridge. It seemed deserted. He turned toward Bandit and motioned toward his faceplate. The other understood. His interphones crackled to life. Prochaska's voice was welcome. "I see him," he broke in. "He's moving up the slope to your right, trying to reach the top of the ridge. Too far for a shot," he added. Crag scrambled into a clearing and scanned the ridge, just in time to see a figure disappear over the skyline. He started up the slope in a beeline for the crest. If he could reach it in time, he might prevent the sniper from crossing the open plain which lay between the ridge and Red Dog. Cops and robbers, he thought. Another childhood game had suddenly been recreated, this time on the bleak plain of an airless alien crater 240,000 miles from the sunny Southern California lands of his youth. Crag reached the ridge. The plain on the other side seemed devoid of life. In the distance the squat needle that was Red Dog jutted above the ashy plain, an incongruous human artifact lost on the wastelands of the moon. Only its symmetry distinguished it from the jagged monolithic structures that dotted this end of the crater floor. He searched the slope. Movement far down the knoll to his right caught his eye. The fugitive was trying to reach a point beyond range of Crag's weapon before cutting across the plain. He studied the terrain. Far ahead and to the left of the invader the crater floor became broken by bizarre rock formations of Backbone Ridge--a great half-circle which arced back toward Red Dog. He guessed that the fantastic land ahead was the fugitive's goal.