The branches were glowing blue from the trapped atmosphere within the containment fields there, giving thousands of klicks of vinous wood and flickering leaves a sort of blue, electric glow, as if the entire inner surface were charged with voltage. And everywhere was life and motion: Ouster angels with hundred-klick wings not only flitted among the branches and beyond the leaves, but were hurled deeper into space—inward toward the sun, more quickly outward past the ten-thousand-klick root systems; a myriad of smaller life-forms shimmered in the blue envelope of atmosphere—radiant gossamers, faery chains, parrots, blue arboreals, Old Earth monkeys, vast schools of tropical fish swimming along in zero-g, seeking out the comet-misted regions, blue herons, flights of geese and Martian brandy fowl, Old Earth porpoises—we passed out of range before I could categorize a fraction of what I was seeing.

Farther out, the size of the largest life-forms and swarms of life-forms became apparent. From several thousand klicks “up,” I could see the shimmering herds of blue platelets, the sentient Akerataeli traveling together. After our first meeting here with the creatures from my cloud planet, I had asked Aenea if there were any more on the Biosphere Startree than the two in the conference.

“A few more,” my friend had said. “About six hundred million more.” Now I could see the Akerataeli moving effortlessly on the air currents from trunk to trunk—hundreds of kilometers apart—in swarms of thousands, perhaps tens of thousands.

And with them came their obedient servants: the sky squids and zeplins and transparent medusae and vast, tendriled gas bags similar to the one that had eaten me on the cloud world. But larger. I had estimated that original monster as perhaps ten klicks long—these zeplinlike work beasts must have been several hundred klicks long, perhaps longer when one factored in the countless tentacles, tendrils, flagella, whips, tails, probes, and proboscises the things sported. I realized as I watched that all of the Akerataeli’s giant beasts of burden were busy with tasks—weaving branches and stems and pods into elaborate bio-designs, pruning dead branches and city-sized leaves from the Startree, wrestling Ouster-designed structures into place or hauling material from one part of the Biosphere to another.

“How many zeplin things are the Akerataeli controlling on the Startree?” I asked Aenea when she was free for a second.

“I don’t know,” she said. “Let’s ask Navson.”

The Ouster said, “We have no idea. They breed as needed for tasks. The Akerataeli themselves are a perfect example of a swarm organism, a hive mind… none of the disc-entities alone is sentient… in parallel, they are brilliant. The sky squids and other ex-Jovian-world creatures have been reproducing as needed here for more than seven hundred standard years. I would venture that there are several hundred million working around the Biosphere… perhaps a billion at this point.”

I stared down at the tiny forms on the dwindling Biosphere surface. A billion creatures each the size of the Pinion Plateau on my homeworld.

Farther out and the gaps between the branches a million klicks overhead and a half million klicks underfoot became apparent enough. The section from which we had come was the oldest and densest, but far along the great inner curve of the Biosphere there were gaps and divisions—some planned, others yet to be filled in with living material. But even here space was busy and filled with motion—comets arcing between roots, branches, leaves, and trunks on precise trajectories, their gift of water being volatilized from the surface by Ouster-aimed and erg-powered heat beams from the trunks and from genetically adapted reflective leaves creating mirrors hundreds of klicks across. Once turned to water vapor, the great clouds drifted across the trailing roots and misted the billion square klicks of leaf surface.

Larger than the comets were the scores of carefully placed asteroids and shepherd moons moving a few thousand or tens of thousands of kilometers above the inner and outer surface of the living sphere—correcting for orbital drift, providing tides and tugs to help the branches grow correctly, throwing shadow on the Biosphere’s inner surface where shade was needed, and serving as observation bases and work shacks for the countless Ouster and Templar gardeners who watched over the project from decade to decade and century to century.

And now, a half a light-minute out and accelerating toward the sun as if the ship were searching for a Hawking-drive translation point, there appeared to be even more traffic in the vast hollow of the green sphere: Ouster warships, all obsolete by Pax standards, with Hawking-drive blisters or giant ramscoop containment fields, old-fashioned high-g destroyers and C³ ships from a long-gone era, elegant sunjammer cargo craft with great curved sails of gleaming monofilm—and everywhere the individual Ouster angels, wings flapping and shimmering as they tacked in toward the sun or hurtled back out toward the Biosphere.

Aenea and the others stepped back inside to continue their discussion. The topic was important—still trying to find a way to stall the Pax from attacking, some sort of feint or distraction that would keep the massing fleet from hurling itself this way—but I had more important things on my mind. As A. Bettik turned to leave the balcony, I touched the android’s right sleeve.

“Can you stay and talk a minute?”

“Of course, M. Endymion.” The blue-skinned man’s voice was as gentle as always.

I waited until we were alone on the balcony, the drone of conversation from within affording us privacy outside, and leaned on the railing.

“I’m sorry we haven’t had more chance to talk since arriving here at the Startree,” I said.

A. Bettik’s bald scalp gleamed in the rich sunlight. His blue-eyed gaze was calm and friendly. “That’s perfectly all right, M. Endymion. Events have proven quite hectic since our arrival. I do concur, however, that this artifact does cause one to find opportunities to discuss it.” He waved his remaining hand at the huge curve of the Startree to where it seemed to fade away near the central sun’s brilliance.

“It’s not the Startree or the Ousters I want to talk about,” I said softly, leaning a bit closer.

A. Bettik nodded and waited. “You were with Aenea on all of the worlds between Old Earth and T’ien Shan,” I said. “Ixion, Maui-Covenant, Renaissance Vector, and the others?”

“Yes, M. Endymion. I had the privilege to travel with her during all the time she allowed others to travel with her.”

I chewed my lip, realizing that I was about to make a fool of myself but having no choice.

“And what about the time when she did not allow you to travel with her,” I said.

“While M. Rachel, M. Theo, and the others remained with me on Groombridge Dyson D?” said A. Bettik. “We carried on with M. Aenea’s work, M. Endymion. I was especially busy working on the construction of…”

“No, no,” I interrupted, “I mean what do you know about her absence?”

A. Bettik paused. “Virtually nothing, M. Endymion. She had told us that she would be away for some time. She had made provisions for our employment and continued work with her… students. One day she was gone and she was to stay away for approximately two standard years…”

“One year, eleven months, one week, six hours,” I said.

“Yes, M. Endymion. That is precisely correct.”

“And after she returned, she never told you where she had been?”

“No, M. Endymion. As far as I know, she never mentioned it to any of us.”

I wanted to grab A. Bettik’s shoulders, to make him understand, to explain why this was of life and death importance to me. Would he have understood? I didn’t know. Instead, attempting to sound calm, almost disinterested—and failing miserably—I said, “Did you notice anything different about Aenea when she returned from that sabbatical, A. Bettik?”