In the year 2019, the Tyrell Corporation has developed advanced robots referred to as replicas, specifically the Nexus-6 models, so lifelike that they can easily be mistaken for humans. These replicas are used for off-world explorations and forced labor. However, after a rebellion by a group of Nexus-6 replicas, they are declared illegal on Earth, punishable by death. To enforce this decree, the Blade Runner unit is established with the grim task of hunting down and eliminating these rogue beings.
In Los Angeles during November 2019, former police officer Rick Deckard (Harrison Ford) is apprehended by officer Gaff (Edward James Olmos) and brought before his previous superior, Bryant (M. Emmet Walsh). Tasked with the dangerous job of a Blade Runner, Deckard is informed that four Nexus-6 replicas have illegally come to Earth. As these models have a mere four-year lifespan, it is suspected they are in search of a way to extend their existence.
Deckard watches footage of a fellow Blade Runner, Holden, conducting the Voight-Kampff test, which differentiates humans from Replicants based on emotional reactions. However, the test takes a dark turn when Leon, a Replicant, kills Holden after being questioned about his mother. Bryant requests Deckard to retire not just Leon but also the trio of other dangerous Replicants: Roy Batty (Rutger Hauer), Zhora (Joanna Cassidy), and Pris (Daryl Hannah). Initially hesitant, Deckard reluctantly agrees after receiving a thinly veiled threat from Bryant.
Deckard begins his mission at the Tyrell Corporation, looking to confirm the Voight-Kampff test's efficacy on the Nexus-6 models. He soon encounters Rachael (Sean Young), Dr. Eldon Tyrell’s assistant, who is an experimental Replicant unaware of her true nature due to implanted memories. These fabricated recollections serve as an "emotional cushion," necessitating a more rigorous examination to determine her status.
As tensions mount, Deckard's pursuit of the Replicants intertwines with their quest to see Tyrell in order to persuade him to prolong their lives. Meanwhile, Roy and Leon explore a Replicant manufacturing facility, which leads them to J. F. Sebastian (William Sanderson), a talented genetic designer closely associated with Tyrell. Rachael, desperate to assert her humanity, visits Deckard, revealing a family photograph. When Deckard reveals the truth about her memories, Rachael departs emotionally distressed. Concurrently, Pris seeks out Sebastian, cunningly earning his trust.
As part of his investigation, Deckard discovers critical clues in Leon’s hotel room, including a photograph of Zhora and a synthetic snake scale that guides him to the strip club where she performs. After confronting Zhora and killing her, Deckard is ordered by Bryant to also "retire" Rachael, who has now gone missing. Leon abruptly attacks Deckard, but Rachael intervenes, killing him with Deckard’s fallen weapon. Back in Deckard's apartment, a moment of intimacy unfolds, leading to a passionate kiss after an unsettling confrontation.
Arriving at Sebastian's residence, Roy informs Pris of their allies' demise. Feeling pity for their plight, Sebastian admits his own impending mortality due to a genetic disorder. Together, they infiltrate Tyrell’s penthouse, where Roy demands an extension of his life. Tyrell explains this is unachievable, leading Roy to express remorse for his actions, which Tyrell acknowledges but ultimately dismisses. In a shocking turn, Roy kills Tyrell after a brief, unsettling kiss. Following this, a fleeing Sebastian meets a similar fate at Roy's hands.
Back at Sebastian’s home, Deckard is ambushed by Pris, whom he manages to kill. Shortly after, a desperate Roy confronts Deckard, initiating a life-or-death chase ending on the rooftop. In a tense moment where Deckard hangs precariously between buildings, Roy, fueled by an unexpected sense of empathy, saves Deckard, enabling him to escape. As Roy's life force diminishes, he poignantly reflects on the transience of existence, stating, > "All those moments will be lost in time... like tears in rain." With that, Roy expires in silence.
Gaff's arrival brings bittersweet news as he reminds Deckard of the fragility of life with the line, > "It's too bad she won't live, but then again, who does?" Upon returning home, Deckard finds Rachael safe in his bed, and as they flee together, he catches sight of an origami unicorn left behind by Gaff, reminding him of the nature of their lives and the uncertainty that lies ahead.
