With me, time was an all-important factor; for even if the man's outcry had not been heard by his comrades above stairs, it seemed quite reasonable that if he did not return to his other duties within a reasonable time, a search for him would be instituted. If I were to escape, I must get out at once; and so, after I made my offer to the man and he ceased his struggling momentarily, I released my grip upon his throat long enough for him to accept or refuse my proposition.

Being a man of intelligence, he accepted.

I immediately bound him with his own harness and, as an added precaution, stuffed a gag in his mouth. Next I relieved him of his dagger, and after groping around on the floor for some time I found the long sword that had fallen from his hand when I first attacked him.

"And now good-bye, my friend," I said. "You need not feel humiliated at your defeat; far better men than you have gone down before John Carter, Prince of Helium." Then I went out and closed and locked the door of the cell after me.

The corridor was very dark. I had had but one brief glimpse of it, or rather of a portion of it, when my food had been brought to me the previous day.

It had seemed to me then that the corridor led straight away from the entrance to my cell, and now I groped my way through the darkness in that direction.

Probably I should have moved slowly along that unknown passageway; but I did not, for I knew, that if the warrior's cries had been heard in the castle above, there might be an investigation; and I most certainly did not wish to meet a body of armed men in that cul-de-sac.

Keeping one hand against the wall to guide me, I moved rapidly forward; and I had gone perhaps a hundred yards when I discerned a faint suggestion of light ahead of me. It did not seem to be the yellowish light of a torch, but, rather, diffused daylight.

It increased in volume as I approached it, and presently I came to the foot of the stairway down which it was shining.

All this time, I had heard nothing to indicate that anyone was coming to investigate; so it was with a feeling of at least some security that I ascended the stairway.

With the utmost caution, I entered the level above. Here it was much lighter. I was in a short corridor with a doorway on either side; ahead of me the passageway ended in a transverse corridor. I moved quickly forward, for I could now see my way quite clearly, as the corridor, although extremely gloomy, was much better lighted than that from which I had emerged.

I was congratulating myself upon my good fortune as I was about to turn into the transverse corridor, when I bumped full into a figure at the turn.

It was a woman. She was probably much more surprised than I, and she started to scream.

I knew that, above all things, I must prevent her from giving an alarm; and so I seized her and clapped a hand across her mouth.

I had just turned the corner into the other corridor when I collided with her; its full length was visible to me; and now, as I silenced the woman, I saw two warriors turn into it at the far end. They were coming in my direction.

Evidently I had congratulated myself too soon.

Unencumbered by my captive, I might have found a hiding-place, or, failing that, I could have lain in ambush for them in this darker passageway and killed them both before they could raise an alarm; but here I was with both of my hands occupied, one of them holding the struggling girl and the other effectually silencing her attempt to cry out.

I could not kill her, and if I turned her loose she would have the whole castle on me in a few moments. My case seemed entirely hopeless, but I did not give up hope. I had come this far; I would not, I could not, admit defeat.

Then I recalled the two doors that I had passed in the short corridor. One of them was only a few paces to my rear.

"Keep still, and I will not harm you," I whispered, and then I dragged her along the corridor to the nearest door.

Fortunately, it was unlocked; but what lay beyond it, I did not know. I had to think quickly and decide what I should do if it were occupied. There seemed only one thing to do, push the girl into it and then run back to meet the two warriors that I had seen approaching. In other words, try to fight my way out of the castle of Ul Vas-a mad scheme, with half a thousand warriors to block my way.

But the room was not occupied, as I could see the moment that I entered it; for it was well lighted by several windows.

Closing the door, I stood with my back against it, listening. I had not looked down at the woman in my arms; I was too intent upon listening for the approach of the two warriors I had seen. Would they turn into this corridor? Would they come to this very room?

I must have unconsciously released my pressure upon the girl's lips; for before I could prevent it, she tore my hand away and spoke.

"John Carter!" she exclaimed in a low tone.

I looked down at her in surprise, and then I recognized her. It was Ulah, the slave of Ozara, the Jeddara of the Tarids.

"Ulah," I said, earnestly, "please do not make me harm you. I do not wish to harm anyone in the castle; I only wish to escape. More than my life depends upon that, so very much more that I would break the unwritten law of my caste even to killing a woman, were it necessary to do so to accomplish my purpose."

"You need not fear me," she said, "I will not betray you."

"You are a wise girl," I said; "you have bought your life very cheaply."

"It was not to save my life that I promised," she said. "I would not have betrayed you in any event."

"And why?" I asked. "You owe me nothing."

"I love my mistress, Ozara," she said simply.

"And what has that to do with it?" I asked.

"I would not harm one whom my mistress loves."

Of course, I knew that Ulah was romancing-letting her imagination work overtime; and as it was immaterial what she believed so long as she helped me, I did not contradict her.

"Where is your mistress now?" I asked.

"She is in this very tower," she replied. "She is locked in a room directly above this one, on the next level. Ul Vas is keeping her there until he is ready to destroy her. Oh, save her, John Carter, save her!"

"How did you learn my name, Ulah?" I asked.

"The Jeddara told me," she replied; "she talked about you constantly."

"You are better acquainted with the castle than I am, Ulah," I said; "is there any way in which I can reach the Jeddara? Can you get a message to her? Could we get her out of that room?"

"No," she replied; "the door is locked, and two warriors stand guard outside it day and night."

I walked to the window and looked out. There seemed to be no one in sight. Then I leaned out as far as I could and looked up. Perhaps fifteen feet above me was another window. I turned back into the room.

"You are sure that the Jeddara is in the room directly above this?" I asked.

"I know it," she replied.

"And you want to help her to escape?"

"Yes; there is nothing that I would not do to serve her."

"What is this room used for?" I asked.

"Nothing, now," she replied; "you see everything is covered with dust. It has not been used for a long time."

"You think it is not likely that anyone will come here?" I asked. "You think I might hide here safely until tonight?"

"I am sure that you are perfectly safe," she replied; "I do not know why anyone should come here."

"Good!" I exclaimed. "Do you really want to help your mistress to escape?"

"With all my heart," she replied. "I could not bear to see her die."

"You can help her, then," I said.

"How?"

"Bring me a rope and a strong hook. Do you think you can do it?"

"How long a rope?"

"About twenty feet."

"When do you want them?"