In 2019 Los Angeles, former policeman Rick Deckard is detained by officer Gaff, and brought to his former supervisor, Bryant. Deckard, whose job as a “blade runner” was to track down bioengineered humanoids known as replicants and “retire” (kill) them, is informed that four replicants are on Earth illegally. Deckard begins to leave, but Bryant ambiguously threatens him and Deckard stays. The two watch a video of a blade runner named Holden administering the Voight-Kampff test, which is designed to distinguish replicants from humans based on their emotional response to questions. The test subject, Leon, shoots Holden on the second question. Bryant wants Deckard to retire Leon and the other three Nexus-6 replicants: Roy Batty, Zhora, and Pris.
Bryant has Deckard meet with the CEO of the company that creates the replicants, Eldon Tyrell, so he can administer the test on a Nexus-6 to see if it works. Tyrell expresses his interest in seeing the test fail first and asks him to administer it on his assistant Rachael. After a much longer than standard test, Deckard concludes that Rachael is a replicant who believes she is human. Tyrell explains that she is an experiment who has been given false memories to provide an “emotional cushion”.
Searching Leon’s hotel room, Deckard finds photos and a synthetic snake scale. Roy and Leon investigate a replicant eye-manufacturing laboratory and learn of J. F. Sebastian, a gifted genetic designer who works closely with Tyrell. Deckard returns to his apartment where Rachael is waiting. She tries to prove her humanity by showing him a family photo but, after Deckard reveals that her memories are implants from Tyrell’s niece, she leaves in tears. Meanwhile, Pris locates Sebastian and manipulates him to gain his trust.
A photograph from Leon’s apartment and the snake scale lead Deckard to a strip club, where Zhora works. After a confrontation and chase, Deckard kills Zhora. Bryant also orders him to retire Rachael, who has disappeared from the Tyrell Corporation. After Deckard spots Rachael in a crowd, he is attacked by Leon, who knocks the gun out of Deckard’s hand and attacks him. As Leon is about to kill Deckard, Rachael saves him by using Deckard’s gun to kill Leon. They return to Deckard’s apartment and, during a discussion, he promises not to track her down. As Rachael abruptly tries to leave, Deckard restrains her and forces her to kiss him. Rachael continues to resist, and Deckard blocks her attempts to leave. He persists in his advances, and she ultimately relents.
Arriving at Sebastian’s apartment, Roy tells Pris that the other replicants are dead. Sympathetic to their plight, Sebastian reveals that because of “Methuselah Syndrome”, a genetic premature aging disorder, his life will be cut short, just like the replicants that were built with a four-year lifespan. Sebastian and Roy gain entrance into Tyrell’s penthouse, where Roy demands more life from his maker. Tyrell tells him that it is impossible. Roy confesses that he has done “questionable things” but Tyrell dismisses this, praising Roy’s advanced design and accomplishments in his short life. Roy kisses Tyrell, then kills him. Sebastian runs for the elevator, followed by Roy, who rides the elevator down alone.[nb 1] Deckard is later told by Bryant that Sebastian was found dead.
At Sebastian’s apartment, Deckard is ambushed by Pris, but he kills her as Roy returns. Roy’s body begins to fail as the end of his lifespan nears. He chases Deckard through the building, ending up on the roof. Deckard tries to jump onto another roof but is left hanging on the edge. Roy makes the jump with ease and, as Deckard’s grip loosens, Roy hoists him onto the roof to save him. Before Roy dies, he delivers a monolog about how his memories “will be lost in time, like tears in rain”. Gaff arrives and shouts to Deckard about Rachael: “It’s too bad she won’t live, but then again, who does?” Deckard returns to his apartment and finds Rachael asleep in his bed. They leave the apartment block together.