Rugged, granitic walls towered before him. Nowhere could he discern an opening through the formidable barrier; yet somewhere into this inhospitable world of stone the green warrior had borne the woman of the red man's heart's desire.
Across the yielding moss of the sea-bottom there had been no spoor to follow, for the soft pads of the thoat but pressed down in his swift passage the resilient vegetation which sprang up again behind his fleeting feet, leaving no sign.
But here in the hills, where loose rock occasionally strewed the way; where black loam and wild flowers partially replaced the sombre monotony of the waste places of the lowlands, Carthoris hoped to find some sign that would lead him in the right direction.
Yet, search as he would, the baffling mystery of the trail seemed likely to remain for ever unsolved.
It was drawing toward the day's close once more when the keen eyes of the Heliumite discerned the tawny yellow of a sleek hide moving among the boulders several hundred yards to his left.
Crouching quickly behind a large rock, Carthoris watched the thing before him. It was a huge banth, one of those savage Barsoomian lions that roam the desolate hills of the dying planet.
The creature's nose was close to the ground. It was evident that he was following the spoor of meat by scent.
As Carthoris watched him, a great hope leaped into the man's heart. Here, possibly, might lie the solution to the mystery he had been endeavouring to solve. This hungry carnivore, keen always for the flesh of man, might even now be trailing the two whom Carthoris sought.
Cautiously the youth crept out upon the trail of the man-eater. Along the foot of the perpendicular cliff the creature moved, sniffing at the invisible spoor, and now and then emitting the low moan of the hunting banth.
Carthoris had followed the creature for but a few minutes when it disappeared as suddenly and mysteriously as though dissolved into thin air.
The man leaped to his feet. Not again was he to be cheated as the man had cheated him. He sprang forward at a reckless pace to the spot at which he last had seen the great, skulking brute.
Before him loomed the sheer cliff, its face unbroken by any aperture into which the huge banth might have wormed its great carcass. Beside him was a small, flat boulder, not larger than the deck of a ten-man flier, nor standing to a greater height than twice his own stature.
Perhaps the banth was in hiding behind this? The brute might have discovered the man upon his trail, and even now be lying in wait for his easy prey.
Cautiously, with drawn long-sword, Carthoris crept around the corner of the rock. There was no banth there, but something which surprised him infinitely more than would the presence of twenty banths.
Before him yawned the mouth of a dark cave leading downward into the ground. Through this the banth must have disappeared. Was it his lair? Within its dark and forbidding interior might there not lurk not one but many of the fearsome creatures?
Carthoris did not know, nor, with the thought that had been spurring him onward upon the trail of the creature uppermost in his mind, did he much care; for into this gloomy cavern he was sure the banth had trailed the green man and his captive, and into it he, too, would follow, content to give his life in the service of the woman he loved.
Not an instant did he hesitate, nor yet did he advance rashly; but with ready sword and cautious steps, for the way was dark, he stole on. As he advanced, the obscurity became impenetrable blackness.