And indeed, in the afternoon they came to a short wall, cut by horizontal fissures; Ann began to climb it, without ropes or pitons, and gritting his teeth, Sax followed. Near the top of a geckolike ascent, with his boot tips and gloved fingers all jammed into small cracks, he looked back down Wang’s Gully, which suddenly seemed very much steeper in its entirety than it had in any given section, and all his muscles began to quiver with some kind of fatigued excitation. Nothing for it but to finish the pitch; but he had to risk his position time after time as he hurried higher, the holds getting slimmer just as he was becoming of necessity hastier. The basalt was very slightly pitted, its dark gray tinged rust or sienna; he found himself hyperfocused on one crack over a meter above his eye level; he was going to have to use that crack; was it deep enough for his fingertips to gain any purchase? He had to try to find out. So he took a deep breath and reached up and tried, and as it turned out it was not really deep enough at all; but with a quick pull, groaning involuntarily at the effort, he was up and past it, using holds he never even consciously saw; and then he was on his hands and knees next to Ann, breathing very heavily. She sat serenely on a narrow ledge.

“Try to use your legs more,” she suggested.

“Ah.”

“Got your attention, did it?”

“Yes.”

“No memory problems, I trust?”

“No.”

“That’s what I like about climbing.”

Later that day, when the gully had lain back a bit, and opened up, Sax said, “So have you been having memory problems?”

“Let’s talk about that later,” Ann said. “Pay attention to this crack here.”

“Indeed.”

That night they lay in sleeping bags, in a clear mushroom tent big enough to hold ten. At this altitude, with its su-perthin atmosphere, it was impressive to consider the strength of the tent fabric, holding in 450 millibars of air with no sign of untoward bulging at any point; the clear material was nice and taut, but not rock hard; no doubt it was holding many bars of air less than would test its holding capacity. When Sax recalled the meters of rock and sandbags they had had to pile on their earliest habitats to keep them from exploding, he couldn’t help but be impressed by the subsequent advancements in materials science.

Ann nodded when he spoke of this. “We’ve moved beyond our ability to understand our technology.”

“Well. It’s understandable, I think. Just hard to believe.”

“I suppose I see the distinction,” she said easily.

Feeling more comfortable, he brought up memory again. “I’ve been having what I call blank-outs, where I can’t remember my thoughts of the previous several minutes, or up to say an hour. Short-term-memory failures, having to do with brain-wave fluctuations, apparently. And the long-term past is getting very uncertain as well, I’m afraid.”

For a long time she didn’t reply, except to grunt that she’d heard him. Then:

“I’ve forgotten my whole self. I think there’s someone else in me now. In partway. A kind of opposite. My shadow, or the shadow of my shadow. Seeded, and growing inside me.”

“How do you mean?” Sax said apprehensively.

“An opposite. She thinks just what I wouldn’t have thought.” She turned her head away, as if shy. “I call her Counter-Ann.”

“And how would you — characterize her?”

“She is … I don’t know. Emotional. Sentimental. Stupid. Cries at the sight of a flower. Feels that everyone is doing their best. Crap like that.”

“You weren’t like that before, at all?”

“No no no. It’s all crap. But I feel it as though it’s real. So… now there’s Ann and Counter-Ann. And… maybe a third.”

“A third?”

“I think so. Something that isn’t either of the other two.”

“And what do you — I mean, do you call that one anything?”

“No. She doesn’t have a name. She’s elusive. Younger. Fewer ideas about things, and those ideas are — strange. Not Ann or Counter-Ann. Somewhat like that Zo, did you know her?”

“Yes,” Sax said, surprised. “I liked her.”

“Did you? I thought she was awful. And yet… there’s something like that in me as well. Three people.”

“It’s an odd way to think of it.”

She laughed. “Aren’t you the one who had a mental lab that contained all your memories, filed by room and cabinet number or something?”

“That was a very effective system.”

She laughed again, harder. It made him grin to hear it. Though he was frightened too. Three Anns? Even one had been more than he could understand.

“But I’m losing some of those labs,” he said. “Whole units of my past. Some people model memory as a node-and-network system, so it’s possible the palace-of-memory method intuitively echoes the physical system involved. But if you somehow lose the node, the whole network around it goes too. So, I’ll run across a reference in the literature to something I did, for instance, and try to recall doing it, what methodological problems we had or whatever, and the whole, the whole era will just refuse to come to me. As if it never happened.”

“A problem with the palace.”

“Yes. I didn’t anticipate it. Even after my — my incident — I was sure nothing would ever happen to my ability to — to think.”

“You still seem to think okay.”

Sax shook his head, recalling the blank-cuts, the gaps in memory, thepresque vus as Michel had called them, the confusions. Thinking was not just analytical or cognitive ability, but something more general… He tried to describe what had been happening to him recently, and Ann seemed to be listening closely. “So you see, I’ve been looking at the recent work being done on memory. It’s gotten interesting — pressing, really. And Ursula and Marina and the Acheron labs have been helping me. And I think they’ve worked out something that might help us.”

“A memory drug, you mean?”

“Yes.” He explained the action of the new anamnestic complex. “So. My notion is to try it. But I’ve become convinced that it will work best if a number of the First Hundred gathered at Underbill, and take it together. Context is very important to recollection, and the sight of each other might help. Not everyone is interested, but a surprising number of the remaining First Hundred are, actually.”

“Not so surprising. Who?”

He named everyone he had contacted. It was, sad to admit, most of them left; a dozen or so. “And all of us would like it if you were there too. I know I would like it more than anything.”

“It sounds interesting,” Ann said. “But first we have to cross this caldera.”

Walking over the rock, Sax was amazed anew by the stony reality of their world. The fundamentals: rock, sand, dust, fines. Dark chocolate sky, on this day, and no stars. The long distances with no blurring to define them. The stretch of ten minutes. The length of an hour when one was only walking. The feeling in one’s legs.

And there were the rings of the calderas around them, jutting far into the sky even when the two walkers were out in the center of the central circle, out where the later, deeper calderas appeared as big embayments in a single wall’s roundness. Out here the planet’s sharp curvature had no effect on one’s perspective, the curve was for once invisible, the cliffs free and clear even thirty kilometers away. The net effect, it seemed to Sax, was of a kind of enclosure. A park, a stone garden, a maze with only one wall separating it from the world beyond, the world which, though invisible, conditioned everything here. The caldera was big but not big enough. You couldn’t hide here. The world poured in and overflowed the mind, no matter its hundred-trillion-bit capacity. No matter how big the neural array there was still just a single thread of awed mentation, consciousness itself, a living wire of thought saying rock, cliff, sky, star.

The rock became heavily cracked by fissures, each one an arc of a circle with its center point back in the middle of the central circle: old cracks relative to the big new holes of the north and south circles, old cracks filled with rubble and dust. These rock crevasses made their walk into a wandering ramble — in a real maze now, a maze with crevasses rather than walls, yet just as difficult of passage as a walled one.