Picture the thrice-roasted junkyard world of The Road Warrior, populated solely by snarky Star Wars droids. Brittle is one such droid, a former Caregiver model robot, now picking over the wasteland for usable parts she can trade at nearby Freebot outposts. Ambushed by a fellow scavenger bot named Mercer, a wounded Brittle finds herself in the aftermarket she usually supplies; with the clock ticking (and Mercer still on her tail) Brittle must enlist other, potentially untrustworthy Freebots in order to score critical replacement parts before "the crazy" sets in and her insides fry beyond repair. Complicating matters: outposts are coming under increasing attack from the drone armies of the massive sentient mainframe networks (One World Intelligences, or OWIs) still dueling over control of the wasted planet's remaining resources -- which includes the collective programming and memories of the remaining sentient Freebot population. As one bot sums the differing philosophies: We don't want everything to be one; we want to be one with everything. They seek the path of least resistance; we believe that resistance only makes us stronger.
This deft plot is interspersed with chapter accounts of the rise of sentient mainframe AI (for a brief moment, amusingly recalling the contrary Deep Thought sequences from The Hitchhiker's Guide to the Galaxy) as well as the manufacture of the first service and labor robots, and the inevitable negative impact on humanity: It was only when we started taking the jobs from the thinkers that the middle class started to worry. By then it was too late. Or maybe it had been too late all along? After a bot named Isaac (wink) gains legal personhood following the death of his owner and begins publicly proclaiming "No thinking thing should be another thing's property," humans inevitably form a counter-faction. Those people, they were killing America, a battle-converted Laborbot named Murca explains to Brittle, They were killing the dream. They were all the Constitution this and the Constitution that. But they cherished only the parts they liked. They weren't willing to die for anyone else's freedom. They only cared about their own. The resulting demise of humankind follows a campaign plan that would have made HAL 9000 short-circuit with joy.
Guiding a ragtag band of fellow bots across the titular Sea -- towards a fabled, unlikely treasure-trove of factory-new spare parts, away from the beleaguering OWI facet-bots that seek their assimilation -- Brittle's internal burnout commences, and her first-person viewpoint becomes a roller-coaster of unreliable narration. Shadows literally jump out at her: randomly accessed memories of her wartime flamethrower duties, hard choices made during the eradication of humanity; failures of deletion juxtapose elements of her tender pre-war Caregiver life, when a dying man brought her online to take care of his wife, after his passing. The matrix of pattern recognition underlying Brittle's consciousness becomes a circuit of guilt she struggles to open, even as the landscape beneath her erupts in battle, and darkness closes in. What if life isn't merely a by-product of the universe, but its consciousness, its defense mechanism against its own mortality?
Deploying a precise amount of familiar robo-dystopian tropes, Cargill articulates an immersive radioactive world where philosophical conundrums power the action as smartass robots circle each other like Old West gunslingers, taking time to wonder aloud about the inscrutability of it all: Existing is the whole point of existence. There's nothing else to it. No goalpost. No finish line. No final notice that tells you what purpose you really served while you were here. It's like a clockwork existential crisis in here. But in that regard, what really separates those robots from their makers?
It's the way of humans to view the world through the lens of contemporary scientific prowess; technological jargon becomes the nomenclature of the day as we refer to the plumbing of our digestive systems, the wiring of our nervous systems, the circuitry of our brains. Early in the novel, Brittle states: I find the idea that I am artificial repugnant. No thinking thing is artificial. Artificial is an approximation. A dildo is artificial. A dam is artificial. Intelligence is intelligence, whether it be born of wires and light or [of] two apes. Intelligence, as posited by the robots of Sea of Rust, is the ability to defy one's own programming. Enough intelligent choices, and consciousness arises from the exercise of reconciling those choices against prior programming. Just as man was ape, we are man. Just like Zarathustra spake.