Now the historical community and the fickle world would forget New Houston in favor of this more exotic discovery — unless I could show that Emma’s journal held the key to the new find. Show that the starship she had refused to join had left the monument as marker and proof of their transplutonian passage; show that it was a monument to the Unrest. I would need more than the brief paragraph in her journal to stem the flood of crackpot theories. It would take an entire case, and the plan for that was clean a search for the Mars Starship Association in the archives at Alexandria.

Another mystery to solve. I should have been pleased at the thought, but still I felt only the sharp distress of exposure, and something other than that which verged on fear, and which I did not recognize. Perhaps we undertake the solution of mysteries as a sort of training, so that we can attempt with some hope of success the deciphering of our selves.

In Burroughs I went to my apartment on campus to store my bags. Kitchen in mahogany and black-green ceramic; living room dominated by a bookcase that extended from floor to ceiling around two walls; a thick silver-gray carpet leading down a skylighted hall to a tiled bathroom the size of the living room, almost; and a bedroom filled by a square bed on a dais. The stupid splendor of the bachelor professor. I couldn’t believe I had had it furnished myself. Who was that Nederland, anyway? No wonder I always wanted to be out on a dig.

I crossed the big campus yard, muttered, “Tear it all out, leave bare chambers of wood and plaster, books piled up, mattress in the corner.” The yard lay above the city center and I paused near the statue of the Princess to look out at it. My year in New Houston had warped my sense of scale, and the skyscrapers by the river, the bridge of the water district, the broad boulevards like spokes of a bent wheel, radiating out to the higher residential areas on the slopes of Isidis Planitia, all of it seemed fantastically large to me, gigantic beyond the ability of city planners to conceive. An entire basin made into a river valley, a city of four million under the open sky: what would the citizens of New Houston have thought? What would we have thought of it, three hundred years before?… The past was a simpler place (I know that’s wrong). Our minds are formed in our youth, and stay the same no matter how long we live. “Come on, fossil,” I told myself. The Princess looked down on me compassionately. “Stone man, go see this circle of ice men.” Students glanced at me, walked on unconcerned.

In the department office everything was the same, of course. Lucinda and Corey greeted me and gave me my mail. I have often thought of the department as family: secretaries as aunts and uncles, colleagues as fierce siblings, students as children. How much closer to me were these people than my biological family. Children, grandchildren, great-grandchildren, great-great, etc. — I don’t know how far it extends — I had seen none of them in decades. Most of them were in the asteroids, or farther out, where the Outer Satellites Council lets anarchy reign. Blood, when you get right down to it, is not much thicker than water. But here in the familiar offices Lucinda asked how the dig was coming, how Hana and Bill were progressing, what Xhosa’s latest complaint was — and what did I think of this remarkable thing on Pluto? “Alien radio receiver,” I said, and they laughed. That’s family for you.

My mail was junk, except for a long handwritten letter from my third wife. She was struggling with a funk, and this letter was part of her therapy. It had taken her a month to compose it, and it read like the diary of a zombie. “I took a walk by the canal. The ice was thick and starred by rocks thrown by little boys.” Poor Maggie. I put the letter away to finish another time. She had written boring letters even when she wasn’t in a funk.

Over in the space center’s big projection room Stallworth, Lewis, Nguyen, and some others I didn’t know were ready and waiting for me. “Roll it,” Nguyen called to the technician.

Black room. Then over the floor appeared the dark ringed plain I had seen in the little photo. A star-thick night sky appeared against the domed ceiling; the sun was two or three times brighter than Sirius, and lay low on the horizon.

“Icehenge at its closest is fifty meters from the geographical north pole,” Nguyen said.

“Icehenge?”

“That’s what they’re calling it.”

“A henge is a circular earthen mound,” I objected.

“The analogy is with Stonehenge,” Nguyen said cheerfully.

“Besides, the liths have been set on the rim of a subdued crater, so that they’re a meter or two above the plain. So you can call the rim your henge.”

“Ridiculous.”

“So where is it?” Stallworth said. I had worked with him before on dating methods, his specialty.

“This holo was made by Arthur Grosjean, the chief planetologist on the Persephone. He gives us the same walking approach that they had. Note the jiggling horizon. It’ll appear in front of us. It’s summer in Pluto’s northern hemisphere, so the megalith is in constant sunlight.”

“Shouldn’t that be megahydor?” I asked caustically.

“You know what I mean. Quiet, here it comes.”

But Stallworth said, “This cratering must have spanned billions of years. How did a planet so far away from everything else get so heavily cratered?”

“There’s no agreement on that,” Lewis said. “One theory is that Pluto was a moon of one of the gas giants, and that after it took the usual heavy bombardment it was cast out to the edge of the system by a near collision.”

“With what?” Stallworth said.

“I don’t know. Ask Velikovsky.” Lewis laughed. “Mountjove claims the cratering is fifteen billion years old, and that Pluto is a captive planet from a very early solar system.”

The horizon was suddenly cracked by a dozen white points, like stars growing to spires of white light. We shut up. The cart that had carried the holo camera jiggled over a submerged crater wall. Soon the entire ring of towers was over the horizon and in our sight. As it came toward us my heart began to flutter painfully. The cart moved between two towers and into the center of the ring. The regolith surface was undisturbed; shouldn’t the construction of the monument have chewed up the area with tracks?

The average towers were ten to fifteen meters tall, two or three meters wide, and one or two thick; some were much bigger. Three of the liths were triangular in cross-section rather than rectangular. One of the big squarish ones had broken off near its base and fallen in toward the center, shattering into scores of sharp-edged white blocks. The holo camera rolled toward this ruin, and when it stopped I walked over to that side of the chamber and stood waist deep in the mirage of an ice boulder.

The others chattered to each other about Saturn’s water ice and the stone circles of Neolithic Britain, etc., but I shut my ears to them and looked at the thing. I fell into the illusion of vast space that the holo created, and tried to get a sense of the place.

“The north pole is beyond the sequence of very large liths,” Nguyen said.

“Be quiet for a while and let us look,” I said.

I walked around and looked at it. Someone had had a good sense of form. It was a human construct, I felt sure; it had the look of mind marking cosmos, like the paintings on a cave wall. Sixty-six liths. Distance between them, ten meters or so. Something brushed the edge of memory and I walked away from it, over to where the others were reading the inscription lith. Deeply cut curved calligraphy, and under that the sixteen slashes.

Was it Stonehenge I was reminded of? No — I had a postcard picture of that in my mind, a little domesticated thing in a protective dome, looking like a piece of sculpture by Rinaldi. And the lintels gave it a different shape. No, it was something else — a moor — the sea like pewter-