chunk: While pursuing his investigation of Lanning's death, Spooner is attacked by a USR demolition machine, and then a squad of NS-5 robots. His boss, Lieutenant John Bergin, worried that Spooner is losing his mind, removes him from active duty. Spooner and Calvin sneak into USR headquarters and interview Sonny. He draws a sketch of his dream: a leader, who Sonny believes to be Spooner, standing before a large group of robots on a hill near a broken bridge. When Robertson learns of Sonny's immunity from the Three Laws, he orders Calvin to destroy him by injecting nanites (replicating nano-scale robots) into his positronic brain. Spooner recognizes the landscape in Sonny's drawing as Lake Michigan, where he discovers an army of NS-5 robots dismantling older models and preparing for a takeover of U.S. cities.