Here he clung and looked once again into the hairy, hideous face of the giant.

"I, Joog. I, Joog," he mumbled. "I can kill! I can kill!" The giant's breath swept over Carter like a blast from a sulphur furnace. There would be no escape from that window!

Once more he dropped down into his cell. This time he commenced a slow circuit of the room, groping his way along the polished ersite slabs that formed the wall. The cobblestone floor was thick with debris. Once, Carter heard the sinister hiss of a Martian spider as he brushed its web.

How long he groped his way around the walls, there was no way of knowing. It seemed hours. Then, suddenly, the deathly silence was shattered by a woman's scream coming from somewhere in the building.

John Carter could feel his skin grew cold. Could that have been the voice of Dejah Thoris?

Once again John Carter leaped toward the faint light that marked the window ledge. Cautiously, he looked down. Joog lay on his back on the flagstones below, breathing as though he were asleep, his great chest rising five feet with every breath. Quietly he started to edge his way along a ledge that ran from the window and disappeared into the shadow of an adjoining tower. If he could make that shadow without awakening Joog!

He had almost gained his objective when Joog growled hoarsely.

He had opened one great eye. Now he reached up and, grabbing Carter by the leg, hurled him into the tower window again.

Wearily, the earthman crawled to the wall of his dark cell and there slumped down against it. That scream haunted his memory. He was tormented by the thought that Dejah Thoris might be in danger.

And where was Tars Tarkas? Pew Mogel must have captured him, too. Carter suddenly sprang to his feet.

One of the ersite slabs at his back had moved! He waited. Nothing came out. Cautiously, he approached the rock and shoved it with his foot. The slab moved slightly inward. Now Carter shoved the stone with all his tremendous strength. Inch by inch he moved it until finally there was room for him to squeeze his body through.

He was still in utter darkness, but his gripping fingers revealed to him that he was in a corridor between two walls. Perhaps this was the way out of his prison!

Carefully he shoved the stone back into position, leaving no trace of his disappearance from the room. The corridor in which he found himself was so low that he was forced to crawl on hands and knees. The low corridor had the stench of age, as if it had been unused for a long time.

Gradually the tunnel sloped more and more downward. Many little side-passages branched off from the main tunnel. There was no light, no noise. Only a faint, pungent odor beginning to fill the air.

Now it was growing lighter. The earthman realized that he must be in the subterranean caverns of the palace. The dim light was caused by the phosphorescent radium glow that is used on all Mars for radiation.

The source of this faint light the earthman suddenly discovered. It was shining through a cleft in the wall ahead. Pushing aside another loose stone, John Carter crawled forth into a chamber.