hind legs was that of a man, but its human-like points were overshadowed by a dozen indelible marks of the beast. A coat of short, dirty gray fur covered the creature from head to foot. Its hands and feet were claw-like travesties of human members. Its pointed, chinless face with its projecting teeth and glittering little beady eyes was that of a giant rodent.

The beast in the clearing was apparently a leader of some sort, for around his throat was a wide collar of gray metal, with its flat surface marked in rudely scratched hieroglyphics. Powell’s heart leaped as he noted the collar. In this creature before him he had his second clue to the whereabouts of Joan Marlowe.

Not only was the collar practically identical to the one worn by the skeleton that had been materialized in the egg back in the laboratory, but the skeleton itself was obviously that of one of the rat-men. Could it be this grotesque horde of human-like rodents that was holding Joan captive in the Cave of Blue Flames?

Powell tried desperately to think of some way of communicating with the gray-collared leader. Then the beast shrilled a command that brought hundreds of the beasts swarming into the clearing from every side, and in the face of the menace of their countless glittering eyes and bared fangs Powell abandoned all thought of attempting to parley with the beasts.

There was another shrill command from the leader, and the horde closed in. Both of Powell’s guns flamed in a crashing leaden hail that swept the close-packed ranks of furry bodies with murderous effect. But he was doomed by sheer weight of numbers.

The rat-men directly in front of the blazing pistols wavered momentarily, but the press of the hundreds behind them swept them inexorably forward. Powell emptied both guns in a last vain effort. Then he was swept from his feet, and the horde surged over him.

Blinded and smothered by the dozens of furry bodies that swarmed over him, he had hardly a chance to even try to fight back. His cartridge-belt and guns, his Silver Belts and his wrist-watch were stripped from him by the dozens of claw-like hands that searched his body. Other claw-hands jerked his arms behind his back and lashed them firmly together with rope.

A blanketing sheet of some heavy fabric was crammed over his head and tied in place so tightly that he was completely blindfolded and half-suffocated. A noose was knotted around his neck. A suggestive jerk of this noose brought Powell lurching to his feet; there was another commanding jerk, and he obediently started walking.

The march that followed soon became torture for the captive. Blindfolded as he was, and having only the occasional jerks of rope to guide his footsteps, he stumbled and fell repeatedly, until his aching body seemed one solid mass of bruises.

As nearly as he could judge, the horde had conducted him nearly two miles when the path abruptly sloped downward. A moment later the sudden coolness of the air and the echoes about him told him that they had entered an underground passage of some kind. After traversing this passage for several yards they emerged into what was apparently a large open area, for he could hear the excited chattering and squealing of countless thousands of rat-men on every side of him.

He was dragged forward a dozen steps more, then brought to a halt. The blindfolding fabric was roughly stripped from his head. For a moment he blinked dazedly, half-blinded by a glare of blue light that flooded the place.

He was standing in a vast cavern. From dozens of fissures high in the rock walls streamed flickering sheets of blue flame which both warmed and lighted the place. There was a weird tingling glow in the air that suggested that the strange blue fires might be electrical in their origin.

Powell looked eagerly around for Joan, but he could see no trace of her. The only other living beings in the big cavern were the swarming thousands of the rat-people. The brutes were apparently too low in the evolutionary scale to have any but the most primitive form of tribal organization.

Sitting on a rude rock throne just in front of Powell was a grotesquely fat, mangy-furred old rat-man who was obviously the king of the horde. Some thirty or forty rat-men, larger and stronger than their fellows, wore the gray-metal collars that apparently marked them as minor leaders.

The great bulk of the horde, numbering far into the thousands, swarmed in the cavern in one vast animal pack, sleeping, feeding, snarling, fighting. As Powell was halted before the king’s throne, most of them abandoned their other pursuits to come surging around the captive in a jostling, curious mob.

The metal-collared leader of the pack that had captured Powell presented the rat-king with the captive’s gun-belt and two Silver Belts, accompanying the gifts with a squealing oration that was apparently a recital of the capture. The old monarch took the trophies with delight.

The two Silver Belts were promptly draped over his own furry shoulders by the king—seemingly following the same primitive love for adornment that inspires an African savage to ornament his person with any new and glittering object he happens to acquire. The rat-king then graciously draped the cartridge-belt and holstered automatics around the shoulders of the metal-collared leader who had captured Powell.

The king turned his attention back to his prisoner. He studied the captive curiously for a moment or two, then squealed a brief command. A score of the rat-men promptly closed in upon Powell, and began herding him toward a far back corner of the big cavern.

Stopping a few yards away from the edge of what seemed to be a wide deep pit in the rock floor, the guard stripped Powell’s bonds from him. Powell made no move to take advantage of his freedom, realizing that the swarming thousands of rodents in the cave made escape out of the question for the moment. He allowed himself to be docilely herded on to the edge of the pit.

And the next moment he exclaimed aloud in delighted surprise as he gazed down at the floor of the pit ten feet beneath him. There, sitting on a low heap of stones on the pit’s sandy floor, white-faced and weary but apparently unhurt, was Joan Marlowe.

The girl’s face brightened in relief as she looked up and recognized him.

“Larry! Oh, thank God you’ve come!”

The leader of the guards motioned for Powell to jump down into the pit. He needed no urging. A moment later he landed lightly on the sandy floor of the pit, and Joan was in his arms.

The rat-men left a dozen of their number scattered as sentries around the edge of the pit. The rest of them returned to the main horde, leaving the prisoners to their own devices.

“I knew that you’d come, Larry, as soon as you got my note,” Joan exclaimed happily. “But how did you ever succeed in finding this Cave of Blue Flame?”

“I didn’t find it myself,” Powell admitted. “I was captured like a boob and dragged here.” He told Joan of his mishaps since arriving in Arret.

The girl nodded when he had finished. “Much the same happened to me, Larry, only the red moon wasn’t shining then. The only light was from what looked like the dim ghost of a big yellow sun. I materialized in Arret almost in the middle of a scouting group of rat-men. They took me captive immediately. When several minutes passed without you and Uncle Benjamin broadcasting the recall wave for me, I knew that something terrible must have happened back in the laboratory, and that I might be marooned in Arret for