Periodically he called his name without receiving an answer. He fumed, wondering what the German had in mind. He couldn't get into Bandit and, besides, he was unarmed. He popped back into Red Dog and looked at the chrono. If Gotch's figures were right the warhead would strike in four minutes. He climbed out of the rill. "Warhead due in less than four minutes," he called into his mike. "Get back into Red Dog, Commander," Richter insisted. Crag snapped irritably: "What the hell are you trying to do." "Commander, many people have crossed the frontier--from East to West. Many others have wanted to." "I don't get you." "I had to come all the way to Arzachel to find my frontier, Commander." "Richter, come back," Crag ordered, his voice level. "There's nothing you can do. You didn't know it but when I landed here I crossed the frontier, Commander. I went from East to West, on the moon." "Richter...?" "Now I am free." "I don't know what you're talking about, but you'd better get back here--and pronto. You'll get massacred if you're on the plain when the rocket hits." Inwardly he was shaken. "There's not a damn thing you can do about Larkwell." "Ah, but there is. He forgot two things, Commander. The oxygen in Baker was only the first." "And the second?" Richter did not answer. Crag called again. No answer. He waited, uncertain what to do next. The ground twisted violently under his feet. The warhead! A series of diminishing quakes rolled the plain in sharp jolts. Missed Arzachel, he thought jubilantly. It missed ... missed. He twisted his head upward. The sky was black, black, a great black spread that reached to infinity, broken only by the brilliance of the stars. Off to one side Betelgeuse was a baleful red eye in the shoulder of Orion. A picture of what was happening flashed through his mind. Somewhere between Alphons and Arzachel thousands of tons of rock were hurtling upward in great ballistic trajectories, parabolic courses which would bring them crashing back onto the lunar surface. Many would escape, would hurtle through space until infinity ended. Some would be caught in the gravisphere of planets, would crash down into strange worlds. But most would smash back on the moon. Rocks ranging in size from grains of dust to giants capable of smashing skyscrapers would fall like rain. "Richter! Richter!" He repeated the call several times. No answer. He swept his torch futilely over the plain. Richter was a dedicated man. If the coming rain of death held any fears for him he failed to show it. He looked up again, fancying that he saw movement against the stars. Somewhere up there mountains were hurtling through the void. He hurriedly descended into the rill, hesitated, then moved into the rocket. He again hesitated before leaving the airlock open. Richter might return.