A dozen paces from him was the sentry moving slowly shoreward toward the watchfire. The man's back was toward Nu, and he was already between Nu and the shore. Nothing could have been better.
The cave man crawled quickly to the platform, and with silent feet ran lightly in the wake of the guard. The man was beside the pile of wood with which he kept up the fire and was bending over to gather up an armful when Nu overtook him. With the speed and directness of a killing lion Nu leaped full upon his quarry's back. Both hands sought the man's throat to shut off his cries for help, and the teeth of the attacker buried themselves in the muscles behind the collar bone that he might not easily be shaken from his advantageous hold.
The sentry, taken entirely by surprise by this attack from the rear, struggled to turn upon his foe. He tore at the fingers at his throat that he might release them for the little instant that would be sufficient for him to call for help; but the vise-like grip would not loosen. Then the victim groped with his right hand for his knife. Nu had been expecting this, and waiting for it. Instantly his own right hand released its grip upon the other's throat, and lightning-like followed the dagger hand in quest of the coveted blade, so that Nu's fingers closed about those of the sentry the instant that the latter gripped the handle of the knife.
Now the blade flew from its sheath drawn by the power of two hands, and then commenced a test of strength that was to decide the outcome of the battle. The Lake Dweller sought to drive the knife backward into the body of the man upon his back. Nu sought to force the knife hand upward and outward. The blade was turned backward. Nu did not attempt to alter this—it was as he would have it. Slowly his mighty muscles prevailed over those of his antagonist, and still his left hand choked off the other's voice. Upward, slowly but surely, Nu carried the knife hand of his foe. Now it is breast high, now to the other's shoulder, and all the time the hairy giant is attempting to drive it back into the body of the cave man.
At the instant that it rose level with the sentry's shoulder Nu pushed the hand gradually toward the left until the blade hovered directly over the heart of its owner. And then, quite suddenly, Nu reversed the direction of his exertions, and like lightning the blade, driven by the combined strength of both men, and guided by Nu, plunged into the heart of the Lake Dweller.
Silently the man crumpled beneath the weight upon him. There was a final struggle, and then he lay still. Nu did not wait longer than to transfer all the coveted weapons from the corpse of his antagonist to his own body, and then, silent and swift as a wraith, he vanished into the darkness toward the forest and the heights above the lake.
Gron, alone in the cave, sat buried in thought. Sometimes she was goaded to despair by recollections of her lost babe, and again she rose to heights of righteous anger at thoughts of the brutality and injustice of Tur. Her fingers twitched to be at the brute's throat. She compared him time and time again with Nu, and at each comparison she realized more and more fully the intensity of her new found passion for the stranger. She loved this alien warrior with a fierceness that almost hurt. She relived again and again the countless little episodes in which he had shown her a kindness and consideration to which she was not accustomed. Among her own people these things would have seemed a sign of weakness upon the part of a man, but Gron knew that no taint of weakness lay behind that noble exterior.
For long into the night she sat straining her eyes and ears through the darkness for the first intimation of his return. At last, when he had not come, she commenced to feel apprehension. He had gone out unarmed through the savage land to wrest weapons from the enemy. Already he might be dead, yet Gron could not believe that aught could overcome that mighty physique.
Toward morning she became hopeless, and crawling within the cave curled up upon the grasses that Nu had gathered for her, and slept. It was several hours after dawn when she was awakened by a sound from without—it was the scraping of a spear butt against the rocky face of the cliff, as it trailed along in the wake of a climbing man.