The Dobelle system was a planetary doublet, twin worlds known as Opal and Quake that spun furiously about their common center of mass. They were joined by the twelve-thousand-kilometer strand known as the Umbilical. The orbit of their mass center about the star Mandel was highly eccentric, and the time of closest approach to the stellar primary induced prodigious land and sea tides in Quake and Opal. That closest approach was known as Summertide. The most recent Summertide had been an exceptional one, because the approach of Mandel’s binary partner, Amaranth, and a gas-giant planet, Gargantua, had led to a lineup of bodies, the Grand Conjunction, that took place only once every 350,000 years.

Very good. Tally knew all that, and he understood it perfectly. Wild as the celestial motions might be, nothing stood in defiance of either logic or physics; to induce such a breakdown, apparently Organics were needed.

“You tell me that a group of humans and aliens converged on Quake and Opal for the last Summertide,” he said to Legate Stancioff. “And they went there voluntarily. But why? Why would anyone go at that time, when the surfaces of the planets were at their most dangerous? They could have been destroyed.”

“We have reason to believe that some of them were.”

“But surely humans and Cecropians and Lo’tfians and Hymenopts don’t want to die?”

“Of course not.” Stancioff was in the human condition that E. C. Tally was coming to recognize as senescence. He was probably no more than ten years away from lapsing to a nontransitional internal state. Already his hands shook slightly as they were talking, in what was clearly a nonfunctional oscillation. “But humans,” Stancioff went on, “and aliens, too, I suppose, though I don’t actually know many aliens — we take risks, when we feel we have adequate reasons. And they all had different interests.