The novel is set in the year 1992 in San Francisco, following an enormous war, World War Terminus, that’s destroyed most of the natural world and left Earth’s surface dangerously irradiated. People with talent and intelligence are sent to colonize other planets, such as Mars, while those who can’t pass the proper tests are left on Earth to eventually die. Because the war destroyed almost all animals, having a pet is the ultimate sign of luxury. Furthermore, science has succeeded in building androids so realistic that it’s become virtually impossible to distinguish them from human beings. These androids are used as workers or assistants on other planets, but some escape and live on Earth, disguised as people. The law enforcement officers on Earth try to hunt down these androids and “retire” them—i.e., kill them. Police officers run elaborate psychological tests on suspects. One such test, the Voigt-Kampff, is designed to measure humans’ natural empathy—androids, who supposedly have no empathy, can’t pass the test.
As the novel begins, Rick Deckard, a seasoned police officer, is contemplating buying a real animal to impress his neighbors—he and his wife Iran Deckard own an electric sheep. Meanwhile, we’re introduced to a mentally challenged man named John Isidore, a “special,” who lives alone in an abandoned apartment building in San Francisco. Isidore is a follower of a strange religion called Mercerism. Followers of Mercerism celebrate empathy by gripping the handles of an “empathy box,” allowing them to feel the emotions and sensations of other people. Mercerism was founded by a man named Wilbur Mercer, who appears before his followers as an old, robed man climbing up a steep hill.
Rick is summoned to his police station. His colleague, Dave Holden, has just been shot and hospitalized by an android, Polokov, whom Dave was trying to track down. Polokov and five other androids have escaped from Mars, where they were sent to perform basic labor, and come to San Francisco. The androids’ model is Nexus-Six, a particularly realistic and unpredictable kind of android. The Rosen organization, the business that manufactures the androids, wants Rick to “retire” them quickly and quietly.
Rick flies to the Rosen Association Building in Seattle, where he meets with Eldon Rosen, a company executive, and his niece, Rachael Rosen. Rachael asks Rick to run the Voigt-Kampff test on her, and Rick does so. Slowly, he realizes that Rachael is really an android. When he accuses Rachael, she and Eldon deny this, and suggest that the Voigt-Kampff test is a poor one. But Rick stands his ground, and it becomes clear that Rachael really is an android after all. Eldon calmly explains that Rachael had no idea she was anything but human—she’d had artificial memories implanted in her brain.
Meanwhile, John Isidore, who works for an electric animal repair company, meets a mysterious woman named Pris Stratton. Pris seems unfamiliar with culture on Earth—in particular, she doesn’t know who Buster Friendly, a famous TV personality, is.
Back in San Francisco, Rick crosses paths with a Soviet police officer who claims to be trying to hunt down androids, too. Rick realizes that the police officer is really Polokov, and Rick shoots him. Next, Rick tracks an android named Luba Luft to the opera house. Rick meets Luba and learns that she, like Rachael, believes that she’s a human being. Suddenly, Luba points a laser gun at Rick and calls the police. A police officer named Crams takes Rick to a police station Rick has never seen before. At the station, Crams and his colleagues, Garland and Phil Resch, interrogate him. When Rick is alone in the police station with Garland, Garland whispers that Resch is really an android, but doesn’t know it—when Resch finds out the truth, he’ll probably kill himself. Then Resch walks back into the room and kills Garland, telling Rick that Garland is an android. Resch seems to have no idea that he’s anything but a human being. Together, Resch and Rick sneak out of the police station—which, according to Resch, is built and inhabited entirely by rogue androids. Rick is disturbed and confused by what he’s seen—he can’t help but wonder whether he is really a human.
Back at the opera house, Resch and Rick track Luba to a museum, where Resch kills Luba in an especially brutal, sudden manner. Rick and Resch decide to administer human-android tests on one another. Rick determines that Resch is human—he’s just a particularly cold, psychopathic kind of human. Resch determines that Rick really is human.
Meanwhile John Isidore gets to know Pris. She explains that she and her android friends have come from Mars, a barren, sad place. She invites her two remaining android friends, Roy Baty and Irmgard Baty, to live with her and John.
Rick has made 3,000 dollars by killing three androids. He immediately spends his money on a real pet goat. Afterwards, he and Iran grip their empathy box together and hear Mercer telling them that it’s impossible to live morally in modern times. Rick gets a call from Rachael Rosen, and they agree to meet in a hotel room.
In the hotel, Rachael and Rick get drunk. Rachael tries to convince Rick not to retire the three remaining androids. Rick and Rachael have sex, and afterwards, Rachael reveals the truth to Rick: she’s known that she’s an android for a long time, and has been secretly having sex with every android bounty-hunter in the city to ensure that they develop empathy for their prey. No bounty hunter has ever continued killing robots after having sex with her—except for Resch. Furious, Rick threatens to kill Rachael, but then realizes he can’t.
Rick tracks down the androids to John Isidore’s apartment. In the apartment, Pris, Roy, and Irmgard watch a TV program in which Buster Friendly exposes Mercerism as a hoax—Wilbur Mercer is just a movie extra posing behind film sets. John finds this news upsetting, but claims that Mercerism will live on. Rick arrives at the apartment and kills Roy, Irmgard, and Pris. His final words to John Isidore are “Don’t take it so hard.”
Rick has killed six androids in 24 hours—a record. He’ll have plenty of money to buy pets now. Instead of returning to Iran, he flies out to the deserts of Oregon (areas that used to be beautiful forests). In the desert, Rick takes futuristic drugs and has a vision in which he fuses with Mercer and climbs a steep hill, but can’t quite make it to the top. In the desert, Rick is amazed to find a toad—a rare, exotic animal. He takes the toad back to Iran, but Iran quickly recognizes that it’s just an electric fake. Confused and exhausted, Rick goes to sleep. While he sleeps, Iran calls the pet store and orders electric flies for the toad to eat. She explains, “My husband is devoted to it.”