To Crush the Moon by Wil McCarthy

black-roofed, three-story wellwood dormitories,
Sealillia
was a kilometer-wide flower on the surface of a featureless ocean. Around it was a low ring, projecting half a meter out of the water; the sea outside was blue and nearly waveless, but within the ring the water was distinctly greenish in hue, and teeming with laughing, splashing humans in various states of undress.
    “It's a model city,” Sandra answered finally. “Larger versions dot the equator from Galapagos to Kiribati, where hurricanes fear to tread. Probably twenty million people altogether. At the moment, I believe we're a thousand klicks north of the Marquesas, or forty-five hundred northeast of Tonga.”
    “Fascinating,” Conrad said, meaning it. Nothing of the sort had been necessary in his own time. In fact, he suspected it would've been illegal, as there was a push at the time to shrink the Earth's population and expand its wilderness areas, by pushing people off into space. Apparently, this hadn't gone well. Still, he wasn't here to admire the scenery, or even the architecture. “Where are my friends?”
    “This way,” she said, pointing, motioning for him to follow as she approached the staircase that ringed the central plinth. “They've got a pair of apartments in Building One.”
    If that was Building One there at the foot of the stairs, then Conrad could see right away that something was going on; there were kids everywhere, but here they were
clustered
. Here they were all facing the same direction: toward a second-floor balcony on which three people stood. Xmary, Feck, and Eustace.
    Conrad's heart leaped at the sight—they looked fine! In fact they looked
beautiful
, much better than they ever had onboard the starship. Over the years of that bitter journey Eustace in particular had grown into a fine, clever, resilient woman, with no way to express or define herself except in terms of the mission. But there she was, standing out over a crowd of strangers like she'd been doing it all her life. Xmary, by contrast, had started as a socialite and become a spacer mainly by accident.
She
looked even better, even more at home, even more smugly pleased with herself. Mission accomplished!
    The three of them were dressed in wellcloth togas of superabsorber black—“sun cloth” it was sometime called, for it could absorb and store many kilowatt-hours of solar energy, and then release it at night to warm the wearer and light her way. Their hair had been cropped close, in a way that gracefully emphasized their age somehow. Conrad felt immediately self-conscious about his own unruly mop, but at least he had combed it. At least he'd let Sandra pick out a pair of pants and a shirt for him—plain, but tasteful.
    “If you insist on putting yourselves in harm's reach,” Xmary was calling down to a crowd of hundreds, “you should at least prepare yourselves for what's to come. That's just my advice, but you'd do well to listen. You need to study this group's tactics. Does anyone here have combat experience?”
    No hands went up, although many a nervous foot was shuffling on the cement.
    “What's she doing?” Sandra asked quietly, turning a funny look on Conrad.
    “Preparing a defense,” Conrad said, as though it were the most obvious thing in the world. Which of course it was; if they truly had been marked for death, then he and his friends had best gird their loins for battle. And with these young'uns hanging around, there were only three options: evict, recruit, or watch them die in the crossfire. Drowned, most likely; the easiest thing to do with a platform like this was to sink it with all hands aboard, then pick off the survivors as they swam. Would Fatalists discriminate between targets and bystanders? It seemed unlikely.
    “But that's the Constabulary's job,” Sandra protested. “Or the local police for this jurisdiction.”
    “Then where are they?” Conrad asked. “If they want to help, that's fine, but we're not going to sit around