Thus it was that the caveman altered his course to the east and he set off through the trees, swinging among the branches with the ease and celerity of little Nobar, the monkey. Now and then, with the agility of long practice, he sent his lithe body hurtling across some gap between trees, to grasp with unerring accuracy the limb his quick eye had selected. Yet notwithstanding his seemingly reckless pace his passage was almost soundless; and though the tangled verdure appeared as a solid wall, only rarely did his flying figure scrape against the riot of vegetation hemming him in. A few minutes later the giant Cro-Magnard swung into the branches of a tree at the edge of a large circular clearing. Even as he reached the broad surface of a bough extending over the floor of the open ground, he caught sight of his old enemy, Sadu, the lion, crouching in the trail almost directly beneath him. Simultaneously he saw Sadu's intended prey: a slender Cro-Magnon youth, some four years younger than Tharn himself, who was standing stiffly erect, facing the lion, a flint-tipped spear poised in his right hand. Tharn felt himself thrill to the boy's unflinching courage even as he recognized its futility, since no human could thus withstand the iron-thewed engine of destruction that was Sadu, the lion. Tharn was given no opportunity to make use of his arrows or grass rope; for even as he observed the two figures below, the lion's tail shot stiffly erect, a shattering roar split apart the jungle stillness and Sadu charged. As a swimmer dives from a springboard, so did Tharn launch himself into space, his right hand snatching the flint knife from the folds of his loincloth as he left the branch. * * * * * Never before had the cave lord thus attacked the king of beasts; but never before had he sought to wrest Sadu's prey, unharmed, from the animal's fangs and claws. As it was, he landed full upon the lion's back, crushing the beast to earth only inches short of its goal. Voicing a startled shriek, Sadu rebounded from the forest floor like a tawny ball and turned to rend his foolhardy attacker. Tharn, however, was not on the ground. His mind, trained from birth to function with lightning-like rapidity, had chosen the only way to prevent his unplanned act from resulting in certain death for himself. And so it was, as his diving body crushed Sadu to the ground, he passed his strong left arm about its neck, locked his powerful legs about its loins, and plunged his flint knife into its side, seeking the savage heart. Roaring, snarling and spitting in a frenzy of rage, Sadu reared high and toppled back upon the human leech. But Tharn's legs locked only the tighter while the heavy knife, backed by biceps like banded layers of steel, sank home again and again.