Their world is a glittering lattice of pods above a spectacular waterfall, surrounded by wilderness teeming with phosphorescent, gloriously varied life.

Inside their arcology, humans lack for nothing. Content in their machine-guided stasis of many cultures, screened from reality by holotechnology and a vast experiential database stored in their own bodies, they buy and sell, eat and sing, consume entertainments and, very occasionally, venture to the more rugged but equally sheltered “Outside” settlement to feel adventurous.

Some can breathe the air, and most of their descendants someday will; this is a young colony: it will be generations upon generations before the majority of humans, all the different phenomes assembled here from a thousand planets, have evolved enough to live free on the surface.

But all has not gone to plan. Long ago, an accident in space cut the machine brains in the arcologies loose from their overseers, the much more sophisticated computers in orbit.

The disaster could not be predicted. Suddenly, those who survive must face a hostile atmosphere, dangerous wildlife, deprivation, and, perhaps most challenging, self agency.

The remaining societal structures overwhelmed, things growing desperate, a group of new friends thrown together from multiple cultural backgrounds rally an expedition to seek aid, against all odds, stalked by two human monsters.