The translator said stiffly for Fraq, “You require some explanation for my acts?”

The Prefect put on his stiff face. “We have asked for none.”

“Yet he will give it.” Natal paused, phrasing from her computer and her own intuition. “He says, ‘I come from a species that has evolved from planets. We harbor great nostalgia for them. Yet now we live in huge habitats at the edge of our solar system, where the light materials—water, air, gases—abound. So a trip through the “bridge works” to your new world is a great boon. It is so unspoiled. Mine is ancient and trampled. We have no high mountains to scale, as in our accident. Long ago we converted ours into useful things. So I asked to sense your rich world in many ways, the ways of my kind. Thank you.’ With that, this noble being reveals much.”

The Prefect blinked at this. He hesitated, then said, “I believe I understand better.”

Fraq spoke again, and the translator said, “Your world may survive in this form for as many as a thousand of your years. Our experience, and our knowledge of the many messages in the Ur Library”—Natal broke off to add, “that’s what he calls the SETI messages, an ancient library”—“all those tell us this.”

Rachel couldn’t resist asking, “You think it’s inevitable that it will change?”

Fraq gazed at her steadily. He carefully pronounced his words in saying, “All species that retain their technology—which is not all species, nor even a majority—destroy their worlds. Then they try to replenish them, using comets from their outer solar system. Asteroids also. But this fails, too, in time. So we, like many others, had to move to the outer regions. We dwell in great containers, which rotate on long arms, to provide artificial gravity. Such is the lot of the old races.”

The prospect was so chilling that her mind retreated, so she did not catch what mannerisms the Prefect went through with Fraq. Then the Prefect said delicately, “So we can begin to discuss larger issues?” Fraq rasped a positive reply.

As Rachel left the meeting she wondered what had triggered this sudden change in the Ythri. Then came a hunch. “A sacrifice,” she murmured to herself. “One of us had to die. Only then would we show we were in earnest.”

Blood sacrifice.

She did not know why she was so sure, but she was.

FRAQ

Again as I addressed my Flock, I invoked our ancient wisdom:

To dare is to lose one’s flight momentarily, to fall. Not to dare is to lose oneself entire.

My speech, sent in dense code in our sigh-sing language, was this: I must explain why I chose as the next challenge the ascent to this world’s highest prominence. I would have flown to the lofty peak of our home world’s tallest, Weathermother, had I enjoyed the chance. So this was a way to return to our old challenges, in company with the Rachel female. You all would have been thrilled to see how their vegetation on mountain slopes echoes ours. There were plants recalling the ancient names: windnest and hammerbranch, amberdragon and starbells, spindly gaunt lightning-rod, jewel-leaf, even trees like unto Ythrian braidbark and copperwood.