When Nu, the son of Nu, regained consciousness daylight was filtering through several tiny crevices in the debris that blocked the entrance to the cave in which the earthquake had found and imprisoned him. As he sat up, half bewildered, he cast his eyes about the dim interior in search of Nat-ul. Not seeing her he sprang to his feet and searched each corner of the cavern minutely. She was not there! Nu stood for a moment with one hand pressed to his forehead, deep in thought. He was trying to marshal from the recesses of his memory the occurrences of his immediate past.

Finally he recalled that he had set forth from the village of his people in search of Oo, as he had been wont to do often in the past, that he might bring the head of the fierce monster and lay it before the cave of Nat-ul, daughter of Tha. But what had led him to believe that Nat-ul should be there now in the cave beside him? He passed his hand across his eyes, yet the same memory-vision persisted—a confused and chaotic muddle of strange beasts and stranger men, among which he and Nat-ul fled through an unknown world.

Nu shook his head and stamped his foot—it was all a ridiculous dream. The shaking of the earth the previous night, however, had been no dream—this and the fact that he was buried alive were all too self-evident. He remembered that he had not found Oo at home, and when the quake had come he had run into the cave of the great beast to hide from the wrath of the elements.

Now he turned his attention to the broken rock piled before the mouth of the cave. To his immense relief he discovered that it was composed largely of small fragments. These he loosened and removed one by one, and though others continued to roll down from above and take their places for a while, until the cave behind him was half filled with the debris, he eventually succeeded in making an opening of sufficient size to pass his body through into the outer air.

Looking about him he discovered that the quake seemed to have done but little damage other than to the top of the cliff which had overhung before and now had fallen from above, scattering its fragments upon the ledges and at the foot of the escarpment.

For years Oo had laired here. It was here that Nu had sought him since he had determined to win his mate with the greatest of all trophies, but now that his cave was choked with the debris of the cliff top Oo would have to seek elsewhere for a den, and that might carry him far from the haunts of Nu. That would never do at all—Oo must be kept within striking distance until his head had served the purpose for which the troglodyte intended it.

So for several hours Nu labored industriously to remove the rocks from the cave and from the ledge immediately before it, as well as from the rough trail that led up from the foot of the cliff. All the time he kept his spear close to his hand, and his stone ax and knife ready in his gee-string, for at any moment Oo might return. As the great cat had a way of appearing with most uncanny silence and unexpectedness it behooved one to be ever on the alert. But at last the work was completed and Nu set forth to search for a breakfast.

He had determined to await the return of the saber-toothed tiger and have the encounter over for good and all. Had not the young men and women of the tribe begun to smile of late each time that he returned empty handed from the hunt for Oo? None had doubted the sincerity of his desire to meet the formidable beast from which it was no disgrace to fly, for none doubted the courage of Nu; but nevertheless it was humiliating to return always with excuses instead of the head of his quarry.

Nu had scarce settled himself comfortably upon the branch of a tree where he could command the various approaches to the tiger's lair when his keen ear caught the sound of movement in the jungle at his back. The noise was up wind from him and presently the scent of man came down the breeze to the sensitive nostrils of the watcher. Now he was alert in this new direction, every faculty bent to discovering the identity of the newcomers before they sensed his presence.

Soon they came in view—two men, Nu and Tha searching for the former's son. At sight of them, Nu, the son of Nu, called out a greeting.