"Do you think I will let her go alone? I will be close by. Na can lead the rat men through a narrow part of the valley. I will be above on the cliffs, waiting to pelt them with stones. Carlson or Grimm can be with me to roll an avalanche of rocks on their heads. "In the meantime, you can take over the unguarded sphere. The rest will be easy." The professor smacked his fist into his palm. "It might work at that. Grimm can go with you. Carlson and Charlotte will go with me." "Why me?" Grimm demanded. "Why not Carlson? Or are you saving him for your daughter?" * * * * * Carlson grabbed Grimm by the shoulder and spun him around. He drove a hard fist into the stout man's face. Grimm stumbled backward. He fell at the cave's entrance. His hand, sprawled behind him to stop his fall, closed over a rock. He flung it at Carlson from a sitting position. It caught Carlson in the shoulder. Gritting his teeth, Carlson charged at Grimm. But Ro moved more swiftly. He caught the white man and forced him back. "This is no time for fighting," he said. "When the Oan are defeated you can kill each other. But not until then." Grimm brushed himself off as he got to his feet "Okay," he sneered. "I'll go with the red man. But when we meet again, it will be a different story." Carlson turned to Ro. "I'll go with you," he said. "Grimm can go with Charlotte and the professor." When they had detailed their plan, the party left the cave. Ro led them into the thickest part of the forest and toward the Oan camp. They moved swiftly. Before long they were at the narrow entrance to the valley. It was about a hundred yards long and twenty feet wide. The walls of the cliff rose almost straight up on both sides. "We leave you here," said Ro to the professor. "Na will lead you to the sphere. She will remain hidden until you have circled away from her. Then she will reveal herself." Ro looked at Na for a long moment before they parted. He grew very proud of what he saw. There was no fear in her eyes. Her small chin was firm. He turned to Carlson. The young Earthman was looking at Charlotte in much the same way. "Come on," Ro said. "If we spend the rest of the morning here, the Oan will try some strategy of their own." Carlson seemed to come out of a trance. He swung around to trail Ro up the sloping part of the mountain. They climbed in silence. Once Ro stopped to look down into the valley. But Na and the others were gone. He felt a pang of regret as he turned to move upward. When they had reached the top, he and Carlson set to work piling rocks and boulders at the edge of the cliff. They chose the point directly over the narrowest part of the valley. If all went well, the Oan would be trapped. They would die under a hailstorm of rock. "You would have liked a more tender goodbye with Charlotte," Ro said to Carlson as they worked. "Was it fear of Grimm that prevented it?"