From storm drains, illegal dumps, and flooded landfills, all of North America’s most advanced technology flows down the Mississippi river – microchips, nano-devices, pharmaceuticals, genetically modified seed – and lodges in the Louisiana delta. Out of this mire emerges a self-organized neural net, drifting in the water: the Watermind. It can freeze, boil, condense, and move – seemingly at will.

CJ Reilly is a brilliant, sexy, self-destructive MIT dropout running away from Cambridge and the suicide of her ironic, emotionally-distant father. She is both infuriating and sympathetic. She is working as a laborer in Devil's Swamp near Baton Rouge, cleaning up a small pollution spill when she and her new lover, Max, discover the mysterious Watermind. Reilly's more interested in investigating it than containing it, but when it kills someone and escapes into the Mississippi, corporations, governments, protesters, the coast guard, and a really wacky underground journalist get involved. And there's no longer any question that it must be destroyed before it reaches the ocean.