A conspiracy of machines – the plot

Chicago in the year 2035: highly intelligent robots are an established part of almost every household. Three rules ensure that they live in harmony and peace with human beings: these forbid the robots from rebelling against their creators, from injuring a human or allowing a human to come to harm through their inaction.
Everyone trusts these practical assistants – until a murder takes place. Detective Spooner, a slightly paranoid cop played by Will Smith, suspects an android of having committed the murder. His investigations uncover a huge threat to the whole world.