mysterious black craft would put in an appearance somewhere near this spot. Penrun knew it all too well. There by the cataract of the White River, half a mile across the plateau from the insect city, he had once been captured.

Next morning when he looked down on the plateau just below the Trap-Door City he laughed triumphantly. There sat the long black-hulled space craft he had seen overhauling the liner.

But a moment later he shook his head dubiously. Too brazen, that landing. It was almost in the insect city. Of course, the ship was large and heavily armed with ray-guns which poked out their sharp snouts here and there about the hull. None the less, an experienced explorer of Titan would never have flung such defiance at the spiders.

The city was feverishly alive with the monsters now. They gathered in groups to stare down at the strange craft, then raced away again, darting in and out of their trap-door homes and streaking here and there across the twisted, tortured granite of the mountainside. The Queen's palace, a vast, raised cocoon of shimmering, silken web, was a veritable bee-hive. Something was brewing!

Abruptly the trap-door homes vomited forth monstrous insects by the thousands which spread with prodigious speed along the mountainside. At an unseen signal they poured down upon the plateau and charged the space-ship.

The black craft's heavy ray-guns broke into life. Attacking monsters curled up and died as the rays bit into their onrushing ranks. The first wave melted, but an instant later the following waves buried the ship.

Insects in the rear darted here and there, dragging away dead and dying spiders. Here was food aplenty! The denizens of the Trap-Door City would live well on their dead for a few days.

Abruptly the attack ceased. The crackling ray-guns were still taking toll as the monsters scurried back to the safety of their city, leaving their dead piled high about the hull of the ship.

Penrun wondered if the monsters would abandon the heaps of their dead. He rather expected that frenzied efforts would be made to retrieve them for food. The problem was solved by those aboard the space-ship, for presently it rose a score of feet in the air and moved a few hundred yards nearer the waterfall that marked the headwaters of the White River.

At once a frantic wave of spiders swept down across the plateau scouring it clean of the dead monsters.

After that the Trap-Door City seemed deserted. Not a spider could be seen near the shining, circular doors. Only here and there crouched a huge, bristly warrior safe behind a jutting rock with his glittering eight eyes fixed on the motionless black ship below.

Again the weary waiting. Penrun could only hope that it would not be long before those aboard the black ship gave him some hint of where the entrance to the Caves might be. Time and again he trained his glasses on the ship only to drop them resignedly. But when noon had passed and the heat of the day was scorching the rock he did not drop his glasses when he looked through them once again. Instead he stood erect in horror and dismay.

A girl had dashed out of the air-lock of the ship. She seemed to be familiar. Then he recognized her as the girl who had tried to rob him aboard the Western Star. Her face was drawn with agony in the stifling, overpowering heat. She had advanced but a few yards, but she was already staggering uncertainly.

What in Heaven's name possessed her to try to venture out in that killing heat? She wasn't even dressed in a space-suit, which would have protected her against heat as well as cold. There was the danger of the monster spiders! Rescue would have to be quick!

Even as the thought flashed through his mind he knew she was past saving. Down from the nearest pinnacle of rock streaked a gigantic spider. The girl saw it, screamed, clutched her throat and fell. Ray-guns of the ship crackled frenziedly. In vain! The insect swept the helpless girl up in its powerful mandibles, sprang clear over the ship and was streaking back up among the rocks in a black blur of speed before the men inside the ship could train the guns on that side, even if they had dared to.

Penrun watched with fascinated dread. To the cavern of the Living Dead! The monster carrying the limp girlish form was now running up through the city toward it, guarded by two other huge insects that had appeared from nowhere. Through the entrance of the cavern they darted and disappeared.

Surely those aboard the ship would make an effort to rescue her, thought Penrun, tense with horror. At least they would retaliate by raying the city with their heavy artillery. But no! The black ship only continued to rest there wavering in the heat. Penrun swore vividly. The cowards! Still, perhaps they were afraid to unlimber their heavy artillery for fear of killing the girl. Or perhaps, which was more likely, they thought she was already dead and devoured. Few persons knew about the Living Death.

Ah, well, he'd forget about her. She was an enemy, she was one of the group that was trying to rob and perhaps kill him. Perhaps her companions knew that she wouldn't be killed for two or three days, and would make an effort to rescue her. And perhaps they wouldn't.

But before an hour had passed Penrun knew that he was going to master his horror of that cavern and save her himself, or die in the attempt. He, and he alone, had been in the cavern of the Living Dead and knew what to expect—the fate that might be his as well as the girl's.

He wondered if that Englishman, that old man with the great beard who said he had known Shakespeare and Bacon personally, was still lying in his silken hammock at the far end of the cave. Know Shakespeare personally? Impossible! Yet was it more impossible than the cavern itself? The man's English was quaint and nearly unintelligible. His description of that comical old space-ship of brass and wood was plausible. Perhaps he had known the Bard of Avon.

Night had descended when Penrun finally emerged from his little ship. The air was bitterly cold, and overhead the stars burned brilliantly. He paused to marvel a little that the Big Dipper, Cassiopeia, and the other constellations appeared just the same out here hundreds of millions of miles from Earth as they did at home. It made one feel infinitely small to realize the pinpoint size of the Solar Universe. He shivered for the temperature was nearly forty below zero, and snapped on the current of his Ecklin electro-heater which was connected with his clothing and would keep him warm even in that cold.

Another suit of slip-on clothes with an Ecklin heater, and his lounging moccasins were in a pack on his back. If he succeeded in releasing the girl, she would need them. The spider monsters didn't leave their Living Dead victims any clothing usually; and little good would it have done the Living Dead if they had.

Swiftly he descended the peak, leaping easily from rock to rock, thanks to the small gravity of the planet, and presently entered the clouds above the insect city. Abruptly the storm broke in all its fury with the shrieking of the gale and driving snow. In the blackness the pencil of light from his tiny flash showed only a few yards through the swirling, driving flakes that bit and numbed his bare face. With pistol ready he forged slowly ahead toward the cavern of the Living Dead.

He bumped into the snow-covered rock before he realized he was close to the place. With every nerve alert and the shrieking, freezing gale forgotten he slipped the flashlight back into its holder and drew another pistol. The door, he recalled, opened inward. It was not fastened, but just inside the entrance crouched a gigantic insect on guard.

Penrun was tense and ready. He kicked the door so viciously that its elastic, silken frame sagged inward under the impact of his foot.