A man without memory is stranded in a world-enveloping city filled with robots gone wild. At his side is a mysterious young woman who claims to know who he is but refuses to tell him. According to The Three Laws of Robotics, "A robot may not injure a human being", which narrows the suspects dramatically when the robots find a dead human body.

The man calls himself Derec; the woman is known as Katherine. Their real identities, along with that of the murder victim and the murderer, are just a few of the life-and-death mysteries the unlikely pair are forced to solve to survive on the fantastic streets of Isaac Asimov's Robot City.

The late Isaac Asimov challenged a talented group of science-fiction writers to resolve the conundrums he set for them in this complex robot mystery set early in the timeline of his robot and Foundation universes.