Several decades have passed since the events recounted in “The Robots of Dawn”. Doctor Amadiro has an unquenchable hatred for Glardia Gremionis for having foiled his plans to dominate the galaxy. With the help of Mandamus, a young and brilliant scientist, he once again hatches a plan to eradicate humanity. To counter it, Gladia is always assisted by Daneel, the humaniform robot, and Giskard, the telepathic android, with numerous abilities but limited by the restrictions imposed by the laws of robotics. And their choices will be all the more difficult as a new law, law zero, will appear...