In 2020, Elias van Dorne, CEO of VA Industries, the world's largest robotics company, introduces his most powerful invention--Kronos, a super computer designed to end all wars. When Kronos goes online, it quickly determines that mankind, itself, is the biggest threat to world peace and launches a worldwide robot attack to rid the world of the "infection" of man. Ninety-seven years later, a small band of humans remain alive but on the run from the robot army. A teenage boy, Andrew and a teenage girl, Calia, form an unlikely alliance to reach a new world, where it is rumored mankind exists without fear of robot persecution. But does this world actually exist? And will they live long enough to find out?
Set in a future Earth (2035 A.D.) where robots are common assistants and workers for their human owners, this is the story of "robotophobic" Chicago Police Detective John Spooner's (Smith) investigation into the murder of Dr. Alfred Lanning (James Cromwell), who works at U.S. Robotics, in which a robot, Sonny (Tudyk), appears to be implicated, even though that would mean the robot had violated the Three Laws of Robotics, which is apparently impossible. It seems impossible because.. if robots can break those laws, there's nothing to stop them from taking over the world, as humans have grown to become completely dependent upon their robots. Or maybe... they already have? Aiding Spooner in his investigation is a psychologist, Dr. Susan Calvin (Moynahan), who specializes in the psyches of robots.