Spoilers ahead.

One of the joys of good space opera, aside from the action, is the discovery of worlds that are meaningfully alien. In award-winning science fiction author Kameron Hurley’s latest novel (Amazon UK), The Stars Are Legion, we get to slither into the fascinating, saliva-covered scenery of the biotech world-ships that make up the mysterious Legion. As civil war rips the Legion apart, Hurley draws us into an intense, Bourne Identity-style mystery about who our heroes are and why they’re fighting.

Zan awakens in a medical bay. She can speak, but she doesn’t know who or where she is. A doctor explains that Zan’s been recycled and reconstructed, hinting that she’s been in this situation many times before. But that’s all Zan knows—well, that and the fact that she has the kind of warrior instincts that let her fight like an MMA master. Plus, she knows an awful lot about how to ride the sentient space motorcycles beasts that the Legion flies from one ship to the other, trailing plumes of yellow exhaust like something out of a 1960s comic book.

Biotech worlds

A myserious woman named Jayd eventually visits Zan and tells her that she’s currently on a planet ship called Katazyrna. Jayd tells Zan that it's time to get back to her mission, penetrating the defenses of another world called Mokshi. And it would be nice if she could do it without getting all her troops killed this time around. Apparently, whenever Zan goes to Mokshi, she’s completely destroyed and loses her memory. But Jayd and her mother, Lord Katazyrna, keep sending Zan back because she’s the only person able to breach Mokshi’s outer perimeter.

Though Zan isn’t sure why she needs to get to the Mokshi, she does want her memory back—and Jayd assures her that those memories are inside the Mokshi. Plus, something else is tugging at Zan’s memory, something about an overwhelming desire and love for Jayd. She wants more than anything to help Jayd on this mission, which she dimly recalls could save the world, or at least the world where she and Jayd live.

Of course, nothing’s that simple. Hurley weaves deftly between Zan and Jayd’s perspectives, giving us clues about what’s really at stake. Zan and Jayd live in the decaying remains of several living megastructures in space, controlled by a rigidly authoritarian society of feuding warlords. We learn that Jayd has somehow betrayed her lover Zan, though Zan doesn’t remember any of that. And Jayd has also come to possess Zan’s womb, which is gestating... something. There are conspiracies within conspiracies, and political infighting that's a cross between gore-soaked medieval fantasy and posthuman bioterror.

When Zan’s mission to Mokshi goes wrong again, she and Jayd are violently separated. That’s when the real action begins. Jayd is married off to the warlord from another world, who promptly attacks Katazyrna and tosses Zan down the recycling chute into a vast cavern of decaying, soon-to-be-reused biomass discarded by every life form on the planet. As the two warriors try to find each other again, Zan has to work her way up from the center of Katazyrna, through layer after layer of an incredible ship inhabited by a bewildering array of people and bizarre ecosystems.

War unending

I cannot emphasize enough how immersive and thrilling the worldbuilding is in The Stars Are Legion. New surprises hide behind every turn in the nested layers of the Legion planet ships. People swap body parts the way we trade phones, the walls throb with arteries, and lakes are made of mucus. Like any great quest narrative, The Stars Are Legion lets us glimpse countless different societies before racing toward the next wonder.

Jayd, meanwhile, gives us a chance to explore the more familiar social conventions that rule these worlds. She’s desperate to get the upper hand in a Machiavellian power struggle to control the least damaged of the Legion’s worlds. Through her eyes, we see how the Legion’s endless wars blur the line between genocide and environmental destruction. Because the world ships are alive, every bomb strike is a murder. People are made from the same biomass that makes trees, water, space motorcycles, and tech. The more that biomass is vaporized, the less there is of everything: people, forests, atmospheres. Yet this desperate situation has only made the warlords more eager to steal resources from other worlds that haven’t been torched yet.

The action pulls us toward the final battle, with Jayd trying to steal a powerful piece of biotech and Zan trying to reach Jayd in time. Though the final reveal is a little pat, the novel’s pyrotechnic creativity is enough to buoy it through a few clunky scenes.

Hurley is wise enough to leave some questions unanswered. We never entirely know what the planet ships are or who made them. They were likely engineered by a long-dead civilization in search of perfectly sustainable ecosystems. But by the time Zan and Jayd's generation grows up, things are breaking down and nobody truly understands the reasoning behind any of it—including the way their own bodies have been engineered.

The potent combination of action and wonder makes The Stars Are Legion a standout. Imaginative without being unrealistic, it offers a glimpse of how radically futuristic technology can exist alongside basic, brutal conflicts that are as old as the first stone tools on Earth.