The story arises from the murder of Rikaine Delmarre, a prominent "fetologist" (fetal scientist), responsible for the operation of the planetary birthing center of Solaria, a planet politically hostile to Earth, whose death Elijah Baley is called to investigate, at the request of the Solarian government. He is again partnered with the humanoid robot R. Daneel Olivaw, and asked by Earth's government to assess the Solarian society for weaknesses.