Carruthers turned upon the girl. "The old chief's words explain everything, Nan. Professor Dahlgren has been here and gone. He lived a lifetime in the span of a few hours earth-time. Now it looks as if we were destined to follow in his footsteps." "I'm not afraid," said the girl. "Nothing can be worse than what we have already passed through." And her eyes softened as she placed her small hands within those of Carruthers. "We have each other, Aaron." He smiled reassuringly and turned to the old chieftain. "I am Carruthers, a friend and assistant to Dahlgren. The girl here is Nanette." The chieftain smiled gravely. "And I am Zark. Welcome to my kingdom, Carruthers and Nanette. We need you here. Now tell me of your world, for long have I waited for a follower of the great Dahlgren to appear before my people." Throughout the remainder of the day Carruthers talked. The shafts of light paled at the end of the short day. Night came, bringing with it a sense of security against the increasing hordes that thundered and trumpeted beyond the borders of the jungle. In the morning Zark instructed Marbo to remain close to Carruthers at all times. So the young scientist left the cavern and ascended the path leading to the top of the plateau. He looked at his watch and compared the second hand with the nucleus atom sailing across the heavens to estimate its speed. * * * * * Days passed as he made his observations. Meanwhile he had searched and found the exact spot wherein he and Nanette had first stepped foot onto the electron. This spot he carefully marked off with a ring of huge boulders carried up by the followers of Marbo. Then he began to calculate upon his pad. There must be no mistakes. He and Nanette must be within the magic circle at the estimated time. Between times he helped Nanette construct their living quarters in the cavern. Zark had furnished them with skins and furs with which to cover the walls. Carruthers made a fireplace of stones and restored the lost art of fire to Zark, Marbo and their followers. Days slipped by like minutes. Short days filled with excursions into the jungles. Carruthers' face soon bristled with a stubble of beard. This lengthened with time. Sharp thorns tore their clothes to ribbons. Nanette, womanlike, cried many times during the nights because of the lack of a mirror and a comb for her untidy hair. But other and more important events soon claimed the attention of the earth people. Day by day the herds of dinosaurs and other monsters of like breed edged closer and closer to the tiny civilization around the plateau. It worried Carruthers so much that he sought out Zark and had him bring the other six members of his tribe together for a council of war. "A complete defensive system, Zark," he told them. "We must make a fortress of the plateau and fill the caverns with food." * * * * *