"Better for you or better for Isaac?"

"Both. We weren't sure he would survive to maturity. Isaac was—is—an experiment, Miss Adams.

Avram was protecting me from what could have been an even more traumatic episode of grief. And beyond that… as much as I wanted to be a parent to Isaac, the boy has a difficult personality. He refused close contact with anyone. As a baby he wouldn't consent to be held. It really was as if he belonged to some new species, as if on the most fundamental biological level he knew he wasn't one of us."

"Because you made him that way," Lise could not help saying.

"True. The responsibility is all ours. And the guilt, of course. All I can say is that we hoped his contribution to our understanding of the universe would redeem the ugliness of his creation."

"Was that something you believed, or something they told you to believe?"

"Thank you for making excuses for me, Miss Adams, but yes, I believed it; all of us believed in it to one degree or another. That's why we came together in the first place. But none of us believed it as confidently and as—I'm tempted to say as heroically—as Avram Dvali. We had doubts, of course we did; we had moments of remorse. It isn't a pleasant story, is it? I'm sure you're asking yourself how we could have contemplated such a thing, much less carried it out. But people are capable of all kinds of acts, Miss Adams. Even Fourths. You ought to remember that." Mrs. Rebka closed her eyes. "And now I'm tired, and I don't have anything further to say."

* * * * *

The others came back with food, bottled water, spare parts, and (miraculously) a second vehicle—another big-tired utility vehicle purchased, Turk said, at ridiculous expense from a larcenous local dealer. The Fourths had more cash than good sense, Turk said, or maybe the sense to know when cash was no good.

She helped Turk load supplies into the vehicles. He moved with easy muscularity, loose-hipped and unself-conscious. There was a certain pleasure in doing the work with him, not thinking about Mrs.

Rebka or Isaac or Dr. Dvali or what might be waiting out in the Rub al-Khali.

"So are you riding with us," he finally asked, "or are you waiting for a bus back to the Port?"

She didn't grace him with an answer. He didn't deserve one.

Because of course she was going with him. Into the big unknown, or wherever it was good people went when they disappeared.

PART FOUR

RUB AL-KHALI

CHAPTER TWENTY-THREE

Brian Gately was safely back in Port Magellan when the second ash-fall struck.