On an alternate Earth, humans create advanced A. I. robots, called sims, that fulfill various roles. A nuclear warhead detonates in Los Angeles due to a sim, leading to a ban on A. I. in the Western world. New Asia supports sims and faces attacks from the US, who seek to eliminate them. The Nomad space station plays a crucial role in their mission to eradicate sims and find Nirmata, the A. I. scientist leader.