Directly ahead lay a complex of low, flat buildings, their walls gently curved to merge with the sand. The air above the complex shimmered like a mirage; was it because of rising heat, Lanier wondered, or something else? He squinted through the tractor’s transparent nose, trying to define the shimmer.

The tractor stopped a few dozen meters from the southernmost building and eased to the sand with a low sigh. The door flowed open and Mirsky stepped out first, Lanier following, watching the man’s reaction closely. The Russian looked around the valley floor, glancing up at the plasma tube. He knows the Stone, Lanier thought. He’s been here before. It doesn’t hold pleasant memories for him.

Svard bent low to exit the tractor and rose gracefully to his full height, large eyes blinking. “This way. Ser Korzenowski is in his private quarters.”

Lanier savored the extra spring in his step. The Stone’s spin imparted a pull of six-tenths of Earth’s gravity on the floor of each chamber, one of the few qualities of the Thistledown that had always been pleasant to him. He remembered, decades ago—before the Death—exercising in the first chamber, swinging vigorously on parallel bars…That reminded him of his once excellent physical conditioning. He had been a gymnast in college.

A hundred meters to the east of the main complex, a smaller anonymous blister of white rose a few meters out of the sand. Svard escorted them along a gravel path and picted a greeting to the dome’s receptor as they approached. A green icon of an outspread hand floated before each of them. “He wants us to come right in,” Svard said. A square door in the wall curled aside, and Konrad Korzenowski emerged, dressed in a simple dark blue caftan.

Lanier had not seen him in person in over thirty years. He had changed little in that time; a simple, spare frame, round face topped by a short crop of pepper-gray hair, a sharp, long nose and penetrating dark eyes. The eyes were more haunted—and haunting—than when they had first met. Having absorbed part of Patricia Vasquez’s mystery, that part of the human personality which could not be synthesized, Korzenowski had seemed to carry an ineffable aspect of the mathematician. His look had been enough to spook Lanier. Patricia was still discernible in the Engineer’s makeup, if anything, more pronounced. What does he feel, with part of her making up his core?

On Earth before the Death, heart-transplants had been commonplace before the perfection of prostheses. How does one feel about carrying a transplanted part of someone’s soul?