Zone 414 is a walled city of state-of-the-art humanoid robots which cater to wealthy clients, providing companionship and sex. When the genius inventor who created the robots and whose corporation runs Zone 414 realizes that his adult daughter Melissa has gone missing inside Zone 414, he hires private investigator David Carmichael to bring her home. David is a former police detective who was forced to retire after he shot his partner and a criminal during a hostage taking. He is still troubled by the death of his wife by suicide and his refusal of several offers of alcoholic drinks suggests he may be trying to stop drinking.The Veidt Corporation tests David by asking him to shoot a woman who pleads for her life; David deduces that she must be a lifelike android and shoots her, passing the test. Next, psychologist Joseph Veidt interviews David to see if he is suitable for job, which requires discretion and willingness to work outside of the law. When he passes both tests, he meets Veidt's brother Marlon, the inventor and executive. Marlon tells David that Melissa, his adult daughter, has gone missing inside Zone 414. He wants David to find her without involving the police, fearing that news of a missing person in Zone 414 might lead to a crackdown on the zone's regulatory exemptions.David pairs up with Jane, a highly advanced and self-aware robot with artificial intelligence, to track down the missing daughter. Jane has developed human-like emotions that transcend the surface depiction of emotions required in her work as a prostitute. She tells David that a man is leaving threatening messages and she has become afraid for her safety.David meets Royale, the pimp who helps wealthy clients select a robot to cater to their sexual needs. He asks her if some wealthy clients are paying to be able to threaten robots like Jane, but Royale denies that she would comply with this request. He asks Royale about Melissa and she tells him that the daughter was pretending to be a robot and was hanging out at a gritty part of the city.As Jane continues to face threats from her stalker, the pair discover Melissa hanging by a noose in an empty warehouse in a boatyard. David returns Melissa's body to Marlon and suggests that the authorities be alerted to Zone 414's dangers. When David meets Joseph Veidt to receive his payment, David goads the psychologist into admitting that he was stalking Jane. He tells David that when Melissa caught him torturing and killing androids, he killed her. Soon after, Joseph arrives at Jane's apartment, and attempts to immobilize her with a hand-held device. Jane is momentarily frozen, but regains mobility and overpowers Joseph. When David returns to see Jane, he offers his gun to Jane and she shoots Joseph dead.Marlon Veidt is seen making adjustments to an android that looks exactly like Melissa (so she may have been a lifelike android all along or Veidt may be replacing the dead human daughter with an android). In the final scene, the Veidt Corporation gets David to record a statement claiming that Zone 414 is safe and they threaten David with legal action if he criticizes the android city. (copied from Wikipedia)