Even with his automatic command of the local language (a gift from the computer and its alterations to his brain), even with this woman's apparently civilized background, this was not the time to explain how he had come from another dimension. Changing the subject, he asked, «What is your name?»

«Narlena,» she answered. Then with a smile she said, «You must have already been moving about in Pura. Tell me, how is it now?»

Blade could not help hesitating. How could she not know what had happened to the city above her head? And if she did not know, how could he tell her that the city lay in ruins and that marauding bands of armed barbarians stalked through those ruins, preying on those of her people bold enough to venture out on to the surface?

Fortunately, he did not have to face the problem at once. Her mobile lips curved upward in a warm smile. «Never mind that for now. Come into my vault with me while I take my tests.» Blade could not help observing that her manner had become noticeably friendlier once she had completed her inspection of his nude body. He decided against taking up his weapons; so far she had accepted him as one of her own people. But displaying his array of marauder weapons might make her change her mind. He followed her into the vault and helped her close the door behind them.

Moments after entering it, Blade knew that his hopes of finding an advanced civilization had been realized. Or at least an advanced technology, he corrected himself; the two were not necessarily the same.

The interior of the vault was about the same size as a large studio apartment. But the walls from the soft, fur-covered floor up to the low, blue-enameled ceiling were almost completely covered with a maze of tubing and cylindrical reservoirs and with squarish metal boxes in a variety of colors at irregular intervals. Some of the boxes had conspicuous dials and lights on their sides. In one corner stood something large. It looked like a mummy case and was mounted on a gimbaled pedestal to give it movement in three directions. There were controls set into the cover, and both halves were lined with maroon plush contoured into a shape very much like the girl's body.

Squarely in the center of the chamber stood an upright cylindrical chamber, apparently of glass, with a vertical section on one side that swung open on almost invisible hinges. The cylinder was filled with some sort of thick gaseous substance, Blade could see its green gray coils writhing and twisting as he watched. But it could hardly be any ordinary gas, for although the door to the cylinder stood wide open, not a single wisp seemed to be escaping into the vault. Blade thought he could see vague hints of dangling wires and straps inside, half-revealed by the eddying and flowing of the gas.

Meanwhile, Narlena had stripped off her clothes and climbed naked into the mummy case. She pressed one of the controls set in the cover, and the cover swung silently closed. For a moment Blade stared uncertainly at its featureless, silvery metal surface. Then a faint hissing filled the chamber. Blade saw a thinner, reddish gas being pumped into the mummy case through a transparent length of tubing. The hissing lasted for perhaps a minute.

Then the lights and dials on the metal boxes along the wall lit up, some of them flashing on and off, while needles wobbled and jerked across dials. Some sort of monitoring process was going on-Narlena's «tests.» Obviously, both the mummy case and the boxes on the wall were part of it. Blade was reminded of films he had seen of medical data on astronauts in space.

The light show went on for perhaps another five minutes; then all the lights and dials went dark simultaneously. The hissing sound began again as the reddish gas was drawn back out of the mummy case through the same tube. The cover swung back, and Narlena stepped out into the vault, a contented look on her face. She sat down on the fur that covered the floor, folded herself gracefully into the lotus position, and looked up at Blade with curiosity, as well as admiration.

«Who are you, Blade?» Her voice was casual, with hardly more concern for his answer than a bus conductor saying, «Fare, please.» One would have thought she was as accustomed to entertaining nude male guests as a Home Dimension hostess might be to having cocktail parties. No, that was not quite correct, thought Blade. Once again he noticed the look in her eyes as they strayed over his massive physique, more than occasionally focusing on his genitals. Obviously, Narlena was physically interested in him.

He decided to tell her the truth about himself. «I am not from your world at all, Narlena. I am from another dimension, and I came here because a computer was attached to my brain and altered it so that I can now see and sense your dimension and speak your language.»

«A lakhyr was attached to your brain? Oh, that is wonderful! Then your people also must have the Dreams. You will be very much at home here in Pura.» She seemed almost about to clap her hands for joy. Then her face fell. «But I do not know if there is an empty vault in working condition for you. Even if there is, I do not know how to set one for anybody but myself. We would have to find a vault master who can analyze any person and adjust a vault for him so that he can have the kind of Dreams he wants most of all. But there are not very many of the vault masters, and we would have to find one of them Waking. I am afraid you will have a long Waking. But there are things we can do during the Waking.» There was a mischievous glint in her eye as she said the last sentence.

Blade nodded absently. His mind was divided between relief at the casual way she had accepted his tale of coming from another dimension and mystification at her constant talk of Dreams and vaults and Waking. Obviously, these had some key role in her society-or in what her society had become. Although Blade had his suspicions, he wanted to learn more precisely what she was talking about.

He shook his head, as if in bewilderment-and he was not entirely faking the bewilderment, either. He said, «Narlena, in my dimension we do not have Dreams. I use the computer only to travel between dimensions. When I am at home, I am waking all the time, except when I am sleeping naturally.» He wondered if that would make any sense to her. It hinged on the accuracy of his guesswork about the nature of Dreams and Waking.

Apparently his guess had been right. Narlena shook her head in sadness and said, «So you have nothing but the Little Dream that is written about in our old books? The ones that show the time before we discovered the real Dreams and how to have them all the time except when we Wake for our tests?»

Blade was beginning to have some vague glimmering of what Narlena was talking about. But her brief speech still sounded strange, as though every third word were in a language he did not understand. Continuing to look bewildered and mystified he said, «Narlena, I do not understand. You seem to be sorry for me and my people because we only have what you call the Little Dream. How is that different from the real Dream that you say your people have?»

Narlena's voice took on an indignant edge. «I do not just say my people have the real Dream-we do! For a hundred years and more, almost two hundred, in fact, we have had them whenever we wanted. Since the Wakers began taking over, a hundred years ago, we have all been Dreaming all the time except for when we also Wake to take our tests. It is the greatest achievement of our people.» There was a note of defiance forced into that last sentence, which made Blade wonder if she really believed what she said.

He still did not entirely understand what she was saying, but now only one out of every four or five words was unintelligible, and the glimmerings of understanding were brightening. If by the Wakers she meant the roving marauders that now ruled the city above, he thought he had a fairly clear picture of what she was talking about. And also a picture of the catastrophe that had befallen her people, a catastrophe brought upon them by their own mastery of science.