He studied the two men at the edge of the plain. It looked like a stalemate. They either had to advance or retreat. Their time was governed by oxygen. If they advanced, they'd be dead pigeons. Prochaska couldn't miss if they chose to cross the clearing. As it was, neither side could get a clear shot at the distance separating them, although the invaders could pour a stream of shells into the open hatch. But Prochaska would be aware of that danger and would have taken refuge to one side of the opening, he decided. There was another complication. The shells were heavy enough to perforate the rocket. Well, he'd worry about that later. He moved his head for a better view of the invaders. The man nearest him had gotten into a prone position and was doing something with the end of his rifle. Crag watched, puzzled. Suddenly the man brought the rifle to his shoulder, and he saw that the end of the muzzle was bulged. Rifle grenade! Damn, they'd brought a regular arsenal. If he managed to place one in the open hatch, the Bandit crew was doomed. Heedless of the other two Red Dog crewmen, he stepped out between the shoulders of rock to gain freedom of movement and snapped his own weapon to his shoulder. He had trouble fitting his finger into the trigger guard. The enemy was spraddled on his stomach, legs apart, adjusting his body to steady his weapon. Crag moved his weapon up, bringing the prone man squarely into his sights. He squeezed the trigger, feeling the weapon jump against his padded shoulder, and leaped back into the protective cover of rock. Something struck his face plate. Splinter of rock, he thought. The watcher on the ridge hadn't been asleep. He dropped to his knees and crawled between the rock spurs to gain a new position. The sharp needle fragments under his hands and knees troubled him. One small rip and he'd be the late Adam Crag. He finally reached a place where he could see the lower end of the ridge. The man he'd shot was a motionless blob on the rocky floor, his arms and legs pulled up in a grotesque fetal position. The vulnerability of human life on the moon struck Crag forcibly. A bullet hole anywhere meant sudden violent death. A hit on the finger was as fatal as a shot through the heart. Once air pressure in a suit was lost a man was dead--horribly dying within seconds. A pinhole in the suit was enough to do it. His eyes searched for the dead man's companions. The ridge and plain seemed utterly lifeless. Bandit was a black canted monolith rising above the plain, seeming to symbolize the utter desolation and silence of Crater Arzachel. For a moment he was fascinated. The very scene portended death. It was an eery feeling. He shook it off and waited. He was finally rewarded by movement. A portion of rock near the edge of the plain seemed to rise--took shape. The dead man's companion had risen to a kneeling position, holding his rifle to his shoulder.