And on this day a thing happened which at once gave the complainers the rest they asked for, and proved the fatality of remaining where they were. A child ran aside from the path its elders were following. The ground here had taken on a brownish hue. As the child stirred up the surface mould with his feet, dust that had settled was raised up again. It was far too thin to have any visible color. But the child suddenly screamed, strangling. The mother ran frantically to snatch him up. The red dust was no less deadly merely because it had settled to the ground. If a storm-wind came now--but they were infrequent under the forgotten planet's heavy bank of clouds--the fallen red dust could be raised up again and scattered about until there would be no living thing anywhere which would not gasp and writhe--and die. But the child would not die. He would suffer terribly and be weak for days. In the morning he could be carried. When night began to darken the sky, the tribe searched for a hiding-place. They came upon a shelf-like cliff, perhaps twenty or thirty feet high, slanting toward the line of the tribesmen's travel. Burl saw black spots in it--openings. Burrows. He watched them as the tribe drew near. No bees or wasps went in or out. He watched long enough to be sure. When they were close, he was certain. Ordering the others to wait, he went forward to make doubly sure. The appearance of the holes reassured him. Dug months before by mining-bees, gone or dead now, the entrances to the burrows were weathered and bedraggled. Burl explored, first sniffing carefully at each opening. They were empty. This would be shelter for the night. He called his followers, and they crawled into the three-foot tunnels to hide. Burl stationed himself near the outer edge of one of them to watch for signs of danger. Night had not quite fallen. Jon and Dor, hungry, went off to forage a little way beyond the cliff. They would be cautious and timid, taking no risks whatever. Burl waited for the return of his explorers. Meanwhile he fretted over the meaning of the stricken child. Stirred-up red dust was dangerous. The only time when there would be no peril from it would be at night, when the dripping rainfall of the dark hours turned the surface of this world into thin shine. It occurred to Burl that it would be safe to travel at night, so far as the red dust was concerned. He rejected the idea instantly. It was unthinkable to travel at night for innumerable other reasons.