Had Dave been a pure scientist, he would have been amazed and baffled by this half-world. The whys and wherefores would have bothered him to the exclusion of other considerations, and he would have been standing there trying to figure it all out when the enemy came along to collect him. Instead, Dave was still alive, or felt that he was, and that was enough for him. Someone else could figure out how and why; his was the line of action; so long as he was able, he was going to continue to live and fight. So when the helicopter dropped down out of the sky near the remote laboratory and disgorged a man carrying a rifle, Dave, the quarry, was sprawled behind a slight ridge in the half-world's terrain, watching through a cleft in the stone outcrop. CHAPTER FOUR The Struggle for Earth The man with the rifle prowled around the ship, looking carefully out across the plains. Then, angrily, he turned and said something at the door of the helicopter, and a second head appeared. There was a short discussion that Dave could not hear, and then the second man came out carrying a tool kit and headed for the lab. The first man got back into the helicopter and took off towards the main building. Dave nodded. It was reasonable to suppose that Claverly, and then Phelps, after finding themselves in this half-world alone, had gone back to the main laboratory to see if they could raise the attention of their friends. Dave himself could have been expected to follow, running after the jeep that had taken the others back to their lab. The hunter expected to find Dave wandering disconsolately around the other lab. When the helicopter had disappeared, Dave arose and scuttled across the plain towards the building he had left. He felt like a battleship on a clear ocean in broad daylight trying to slink unseen behind an enemy, but there seemed no way to avoid it. At any rate, the workman was paying no attention to his surroundings. Within the walls of the laboratory, the workman was unlimbering his tool kit. He was an efficient workman. It was his job to repair the television camera and it was his cohort's job to track down and dispose of Dave. He went to work on this basis and ignored the possibility that Dave might be stalking him--until Dave came silently up behind him and kicked the small sectional ladder out from beneath the workman's feet. Dave's fist came plunging through the windmill of flying arms and legs and connected solidly beneath the workman's ear. Startled, off-balance, and then slugged, the workman came to earth with a dull thud and sprawled motionless. Dave snarled and made doubly sure with a thrusting heel-kick against the workman's jaw and throat. The workman was not the first man to die from such a kick.