To my eyes the stone was solid, as solid as it had ever been. But my hand had sunk in up to the wrist.

"Maelen!"

She needed no call. She was already padding towards me. Door—where had the invisible door come from?

"Think door–think it! See a door in your mind!"

I obeyed her. Door—there was a door there—of course there was. My hand had gone through the opening. There might be an illusion to deceive the eye, but there was nothing now to baffle touch. I rested my other hand on Maelen's head and "we moved resolutely forward together into what appeared solid, unbroken stone.

Again we passed abruptly from light to dark. But also, as if a portal had slammed shut behind us, the humming was instantly silenced. I gave a sigh of relief.

"Is this your way?" I asked. Though how she could be certain of that in the dark, I did not know.

"I cannot be sure. But it is a way. We must keep together."

I left my hand on her head as she crowded against me. So linked, we went on, very slowly and cautiously, my other hand outstretched before me to warn of anything which might rise in our path.

Shortly thereafter I found a wall, traced along it until there was another way open to the left. Long ago I had lost all sense of direction, and Maelen confessed to a similar disability. We could do little until we found some lighted way. That we might not do so was a horror we refused to give mind-room to.

Whether the Thassa shared the ancient fear of the dark with my own race, I did not know. But the sense of compression, of stifling pressure, returned. Save that this time I did not walk with my arms bound to my sides.

"Left now—"

"Why? How do you know?"

"Life force in that direction."

I tried mind-probe for myself. She was right—a flicker of energy. It was not the high flow I associated with the aliens, but more like such as I could pick up when not too far from a crew member. And there was an opening to the left.

How far we were from the chamber of the globes now I could not guess. But a lighting of the way cheered us—and that grew ever brighter.

Only now there was sound also. Not a mutter of voices, but rather the clank of metal. Maelen pushed against me.

"He, the one who wears Griss's body—ahead!"

I tried no probe. I wished I could do just the opposite, reduce all mental activity so far down the scale he could not pick up any hint of us in return. I had not forgotten how easily he had found me out when I had spied on the jacks.

"He is one-minded now," Maelen told me, "using all his power for something which is of very great importance to him. We need not fear him, for he puts all to one purpose."

"And that?"

She did not reply at once. Then—

"Lend me of your sending—"

It was my turn to hesitate. To strengthen any mind-seek she might send out could make us more accessible to discovery. Yet I trusted her enough to realize that she would not suggest such a move unless she thought we had a fair chance. So I yielded.

Her probe sped out, and I fed my own energy to it. This we had not often done, so it was a relatively new experience for me, bringing with it an odd sensation of being pulled along in a current I could not fight. Then a blurred mind-picture came.

We seemed to be hanging in the air over a pit, or rather we were in the apex of one of those pyramid chambers. Below a robo was blasting away at the foot of one wall. There was already a dark cavity there; now the machine was enlarging that.

Behind the worker stood Griss. He did not hold any control board. It would appear that he was able to keep the robo at work without that. And his attention was completely absorbed by what he was doing. But that feverish desire which drove him was like a broadcast. He did not hold his defenses now, but fastened avidly on what he sought—an ancient storehouse of his kind, perhaps containing machines or weapons. His need was like a whiff of ozone. A whiff, I say, because I caught only the edge of it. Around the chamber, well above the level at which the robo worked, was another of the ledge ways. This ran across one wall, leading from one door to another. And without needing to be told, I recognized that this was the path we must follow.

Whether we could do it without attracting attention from below was another matter. But now that hole the robo battered was larger. The machine wheeled back, became inert. And the alien hurried to the break, disappeared through it.

"Now!"

We sped along the lighted corridor, and it was only a short distance until we ventured out on that ledge. It was so close to the apex of the pyramid that the opposite wall leaned very close. Maelen found it easier to take that route than I, for I could not stand erect but had to go on hands and knees.

Nor did I waste any time looking back at the hole the robo had opened. To reach the door on the other side, scramble within, was all I wanted.

"We made it!"

"For now, yes," she answered me. "But—"

She swung around, her head down. Her dusty body quivered.

"Krip! Krip, hold me!" It was a cry for help, coming so suddenly, without warning, that I was startled. Then I half threw myself over her, grasping her tightly around the body, holding on in spite of her struggles for freedom.

It was no longer Maelen whom I held so, but an animal that growled and snapped, struck out with unsheathed claws. Only by pure chance did I escape harm. Then she collapsed against me, her breath coming in deep gasps. There were flecks of white foam at the corners of her jaws.

"Maelen, what is it?"

"The calling—it was stronger this time, much stronger. Like—like to like!"

"What do you mean?" I still held her but she was far from fighting now. As if her struggle had exhausted her, she was in nearly the same condition in which I had earlier found her.

"The dream—she of the cat crown." Maelen's thoughts did not make a completely coherent pattern. "She is—akin to Thassa—"

But I refused to believe that. I could see no resemblance between her and the Maelen I had known.

"Maybe not to the sight," Maelen agreed. "Krip– is there more water?" She was still panting, the sound of it close to human sobbing. I found the flask, poured a little in her mouth. But some I must save, for we did not know when we could replenish that small supply.

She swallowed greedily, but she did not press me for more.

"The mind-call—the dream—I knew their like. Such are of Thassa kind."

I had a flash of inspiration. "Could it be adjusted? That is—having discovered you, could the pattern be altered to a familiar one, thus with a better chance of entrapping you?"

"That may well be so," she admitted. "But between me and that other there is something—Only when I face her, it will be on my terms and not hers, if you will give me of your strength as you did this time •when she called."

"You are sure it was she? Not the one we just saw?"

"Yes. But when I go it will be at a time of my choosing. Which is not yet."

Having taken a mouthful of water myself, I brought out an E-ration tube, which we shared half and half. Made for nourishment during times of strain, it was high in sustenance and would keep us going for hours to come.

There was no sound from the chamber where the robo must still be on guard beside that hole. I wondered very much what the alien sought beyond the battered wall. But Maelen did not mention that as we went. On the contrary, she asked a question so much apart from the matters at hand I was startled.

"Do you think her fair?"

Her? Oh, I realized, she must mean the alien woman.

"She is very beautiful," I answered frankly.

"A body without blemish—though strange in its coloring. A perfect body—"

"But its mind reaches for another covering. That which walks in Griss was also perfect outwardly, yet its rightful owner saw fit to exchange with Griss. And I was taken there to exchange with another one. Are they in stass-freeze, I wonder?"