Seth Brundle, a brilliant but eccentric scientist, meets Veronica "Ronnie" Quaife, a science journalist, at a press event. He takes her back to his home and laboratory and shows her his invention: a set of "telepods" that allows instantaneous teleportation between them. Seth convinces Ronnie to keep the invention secret in exchange for exclusive rights to the story, and she documents his work. Although the telepods can transport inanimate objects, they mutilate live tissue, as demonstrated when a baboon is turned inside-out during an experiment. Seth and Ronnie begin a romantic relationship. Their first sexual encounter inspires Seth to reprogram the telepod to understand the makeup of living tissue. After he successfully teleports a second baboon, Ronnie hurriedly leaves to confront her editor Stathis Borans about his threat, spurred by his jealousy of Seth, to publish the story without her consent. Embittered and convinced she is rekindling her relationship with Stathis, Seth teleports himself alone, unaware that a housefly has slipped inside the transmitter pod with him. He emerges from the receiving pod seemingly normal. Seth and Ronnie later reconcile. Seth starts to exhibit increased strength, stamina, and sexual potency, which he attributes to the teleportation "purifying" his body. Ronnie grows concerned about Seth's changing personality and the strange, bristly hairs growing from a wound on his back. Seth becomes arrogant and violent, insisting that the teleportation process is beneficial, and tries to force Ronnie to undergo teleportation. When she refuses, he abandons her, goes to a bar and partakes in an arm-wrestling match, where he leaves his opponent with a compound fracture. He brings a woman named Tawny back to his warehouse to have intercourse. When Seth tries to coerce her into teleporting, Ronnie stops him and Seth throws her out as well. When his fingernails begin falling off, Seth realizes something is wrong. He reviews the telepod's computer and discovers that there was a fly in the pod with him. The computer, confused by the presence of two lifeforms, fused him with the fly at the molecular-genetic level. Seth continues to deteriorate, losing body parts and becoming less human in appearance. After several weeks, he reconnects with Ronnie and says he is becoming a hybrid of human and insect he nicknamed "Brundlefly." He has begun vomiting digestive enzymes onto his food to dissolve it and gained the ability to cling to walls and ceilings. He also realizes that he is losing his human reason and compassion, driven by primitive impulses he cannot control. Seth installs a fusion program into the telepod computer, planning to dilute the fly genes in his body with human DNA. Ronnie learns that she is pregnant by Seth, but does not know if the conception occurred before or after Seth's genes were corrupted. She worries that the child will not be human, and has a nightmare of giving birth to a giant maggot. She visits Brundle in order to break the news to him, but he warns her that he will harm her if she continues to visit. Terribly upset, she has Stathis persuade a doctor to perform an abortion in the middle of the night. Having overheard their conversation, Seth abducts Ronnie and begs her to carry the child to term, since it may be the last remnant of his humanity. Stathis breaks into Seth's lab with a shotgun, but Seth incapacitates him with his corrosive vomit. Seth reveals his desperate plan to Ronnie: he will use the telepods to fuse himself and her, together with their unborn child, into one entity. As Seth drags her into one of the telepods, she accidentally rips off his jaw, triggering his final transformation into an insectoid-human "Brundlefly" creature, shedding his decayed human skin. Brundlefly traps Ronnie inside the first telepod and enters the other, planning to use the prototype pod as the receiver of the combination of pods 1 and 2. The wounded Stathis uses his shotgun to sever the cables connecting Ronnie's telepod to the computer, allowing Ronnie to escape. The damage causes telepod 2 to malfunction and Brundlefly attempts to smash his way through the door, only for the pod to activate just as he is stepping out, fusing the creature to a piece of the door and other components. The prototype pod receives the Brundlefly/Telepod fusion successfully; as the door opens, the resulting creature falls out of the door and to the ground. He crawls to Ronnie and silently requests for her to end his misery by aiming Stathis' shotgun barrel, which she had picked up, at his own head. She eventually, and tearfully, shoots and kills him, falling to her knees in despair.

On 29 April, Sergeant Neil Howie of the West Highlands Constabulary journeys by seaplane to the remote, verdant Hebridean island of Summerisle to investigate the disappearance of a young girl, Rowan Morrison, about whom he has received an anonymous letter. Howie, a devout Christian, is disturbed to find the islanders paying homage to the pagan Celtic gods of their ancestors, with churches having fallen into disuse. They copulate openly in the fields, include children as part of the May Day celebrations, teach children of the phallic association of the maypole, and one places a toad in a child's mouth to cure a sore throat. The islanders appear to be trying to thwart his investigation by claiming that Rowan never existed. While Howie is staying at the Green Man Inn, the landlord's daughter attempts to seduce him, but he resists, explaining that he is engaged and must reserve sex for marriage. He notices a series of photographs celebrating the annual harvest, each featuring a young girl as the May Queen. The photograph of the most recent celebration is missing and the landlord tells him it was broken. At the local school, Howie asks the students about Rowan, but all deny her existence. He checks the school register and finds Rowan's name. He questions the schoolteacher, who directs him to Rowan's grave. The next day, 30 April, Howie meets the island's leader, Lord Summerisle, grandson of a Victorian agronomist, to get permission to exhume Rowan's body. Summerisle explains that in 1868, his grandfather developed strains of fruit trees that would prosper in Scotland's climate and encouraged the belief that returning to the old gods would bring prosperity to the island among the previously Christian population. Due to the bountiful harvests, the island's other inhabitants gradually embraced paganism, and the Christian ministers fled to the mainland. Exhuming Rowan's grave, Howie finds that the coffin contains only the body of a hare. He also finds the missing harvest photograph, showing Rowan standing amidst empty boxes; the harvest had failed for the first time since the orchards were established. His research reveals that a human sacrifice is offered to the gods in the event of crop failure. He concludes that Rowan is alive and will soon be sacrificed to ensure a successful harvest this season. The following morning, on May Day, Howie seeks assistance from the mainland and returns to his seaplane, only to discover it no longer functions and its radio is damaged; he cannot leave or call for help. Later that day, during the May Day celebration, Howie subdues the innkeeper and steals his costume and mask of Punch (the Fool) to infiltrate the parade, involving a long sword dance. Rowan is eventually revealed. Howie sets her free and flees with her into a cave. Exiting it, they are intercepted by the islanders, to whom Rowan happily returns. Summerisle tells Howie that Rowan was never the intended sacrifice — Howie is. He fits their gods' four requirements: he came of his own free will, he has "the power of a king" by representing the law, he is a virgin, and he is a "fool" by falling for their deception. Howie warns Summerisle and the islanders that the crops are failing due to the unsuitability of the climate, and that the villagers will turn on Summerisle and sacrifice him next summer when the harvest fails again, but his pleas are ignored. The villagers force Howie inside a giant wicker man statue along with various animals, set it ablaze, and surround it, singing the Middle English folk song " Sumer Is Icumen In ". Inside the wicker man, Howie recites Psalm 23 and prays to God. Howie and the animals burn to death as the head of the wicker man collapses in flames, revealing the setting sun.

Joseph (Jan Nowicki) travels through a dream-like world, taking a dilapidated train to visit his dying father, Jacob, in a sanatorium. When he arrives at the hospital, he finds the entire facility is going to ruin and no one seems to be in charge or even caring for the patients. Time appears to behave in unpredictable ways, reanimating the past in an elaborate artificial caprice. Though Joseph is always shown as an adult, his behavior and the people around often depict him as a child. He befriends Rudolf, a young boy who owns a postage stamp album. The names of the stamps trigger a wealth of association and adventure in Joseph. Among the many occurrences in this visually potent phantasmagoria include Joseph re-entering childhood episodes with his wildly eccentric father (who lives with birds in an attic), being arrested by a mysterious unit of soldiers for having a dream that was severely criticized in high places, reflecting on a girl he fantasized about in his boyhood and commandeering a group of historic wax mannequins. Throughout his strange journey, an ominous blind train conductor reappears like a death figure. He also has a series of reflections on the Holocaust that were not present in the original texts, reading Schulz's prose through the prism of the author's death during World War II and the demise of the world he described.

The film begins with a pair of floating disembodied lips welcoming the audience to a science fiction double feature (" Science Fiction/Double Feature "). Throughout the film, a criminologist from an unspecified point in the future narrates and provides commentary on the events. Following the wedding of their friends, a naïve young couple, Brad Majors and Janet Weiss, get engaged and decide to celebrate with their high school science teacher Dr. Scott, who taught the class where they first met (" Dammit Janet "). En route to Scott's house on a dark and rainy night, they get lost and suffer a flat tyre. Seeking a telephone to call for help, the couple walks to a nearby castle (" Over at the Frankenstein Place ") where a party is being held. They are accepted in by the strangely dressed inhabitants, led by the butler Riff Raff, the maid Magenta, and a groupie named Columbia, who dance to " The Time Warp ". Dr. Frank-N-Furter, a transvestite mad scientist, introduces himself and invites them to stay for the night (" Sweet Transvestite "). With the help of Riff Raff, Frank brings to life a tall, muscular, handsome blond man named Rocky ("The Sword of Damocles"). As Frank vows he can improve Rocky into an ideal man in a week ("I Can Make You a Man"), Eddie, a motorcyclist with a bandaged head, breaks out of a deep freeze ("Hot Patootie – Bless My Soul"). Frank kills Eddie with an ice axe, justifying it as a " mercy killing ". Rocky and Frank depart for the bridal suite ("I Can Make You a Man (Reprise)"). Brad and Janet are shown to separate bedrooms, where Frank visits and seduces each one disguised as the other. Meanwhile, Riff Raff torments Rocky, who flees the suite. Janet, having learned of Brad's dalliance with Frank, discovers Rocky cowering in his birth tank. While tending to his wounds, Janet seduces Rocky as Magenta and Columbia watch from their bedroom monitor ("Touch-a, Touch-a, Touch-a, Touch Me"). Dr. Scott, now a government investigator of UFOs, comes to the castle in search of his nephew Eddie, who sent him a letter implying part of his brain was removed by aliens. Everyone discovers Janet and Rocky together, enraging Frank. Magenta summons everyone to an uncomfortable dinner, which they soon realise has been prepared from Eddie's mutilated remains ("Eddie"). In the chaos, Janet runs screaming into Rocky's arms, provoking a jealous Frank to chase her through the halls to the lab, where he uses his Medusa Transducer to turn Dr. Scott, Brad, Janet, Rocky, and Columbia into nude statues ("Planet Schmanet Janet/Wise Up Janet Weiss"/"Planet Hotdog"). After dressing the statues in cabaret costumes, Frank "unfreezes" them and leads them in a live cabaret floor show, complete with an RKO tower and a swimming pool ("Rose Tint My World"/"Don't Dream It, Be It"/"Wild and Untamed Thing"). Riff Raff and Magenta interrupt and announce that due to Frank's extravagance, they are declaring mutiny and returning to their home planet of Transsexual, Transylvania. Frank makes a desperate final plea ("I'm Going Home"), but is ignored as Riff Raff kills both him and Columbia with a laser. An enraged Rocky climbs the tower with Frank's body as Riff Raff shoots him several times with the laser, but it does not work on him. When they climb too high, the tower collapses and Rocky plunges to his death in the pool. The castle lifts off into space, and Brad, Janet, and Dr. Scott are left crawling in the smog and dirt, confused and disorientated, as the criminologist concludes that the human race is equivalent to insects crawling on the planet's surface: "lost in time, and lost in space... and meaning" ("Super Heroes").

In 1462, Vlad Dracula returns from a victory in his campaign against the Ottoman Empire to find his beloved wife Elisabeta has committed suicide after his enemies falsely reported his death. A Romanian Orthodox priest tells him that his wife's soul is damned to Hell for her suicide. Enraged, Vlad desecrates the chapel and renounces God, declaring he will rise from the grave to avenge Elisabeta with all the powers of darkness. He then stabs his sword into the chapel's stone cross and drinks the blood that pours from it, becoming a vampire. In 1897, solicitor Jonathan Harker takes the elderly Transylvanian Count Dracula as a client from his colleague R. M. Renfield, who has gone insane and is now an inmate in Dr. Jack Seward 's asylum. Jonathan travels to Dracula's castle in Transylvania to arrange Dracula's real estate acquisitions in London. There, he meets Dracula, who finds a picture of his fiancée Mina Murray and believes she is Elisabeta reincarnated. Dracula leaves Jonathan to be fed upon by his brides, while he sails to England with Transylvanian soil, taking up residence at Carfax Abbey, which he recently purchased. In London, Dracula, in werewolf form, hypnotically seduces and bites Mina's best friend Lucy Westenra, with whom Mina is staying while Jonathan is in Transylvania. Lucy's deteriorating health and behavioral changes prompt former suitors Quincey Morris and Dr. Seward, along with her fiancé Arthur Holmwood to summon Dr. Abraham Van Helsing, Seward's mentor, who recognizes Lucy as being the victim of a vampire. Dracula, appearing young and handsome during daylight, meets and charms Mina. Mina develops feelings for Dracula, accompanying him on several outings. When Mina receives word from Jonathan—who has escaped the castle and recovered at a convent—she travels to Romania to marry him. A heartbroken Dracula transforms Lucy into a vampire. Van Helsing, Holmwood, Seward, and Morris kill the undead Lucy the following night. After he and Mina return to London, Jonathan and Van Helsing lead the others to Carfax Abbey, where they destroy the Count's boxes of soil. Dracula enters the asylum and kills Renfield for warning Mina of his presence. He visits Mina, who is staying in Seward's quarters, and confesses that he murdered Lucy and has been terrorizing Mina's friends. Though furious at first, Mina admits that she still loves him and remembers Elisabeta's previous life; at her insistence, Dracula begins transforming her into a vampire. The hunters burst into the bedroom, and Dracula, in a bat humanoid form, claims Mina as his bride before escaping as a swarm of rats. As Mina changes, Van Helsing hypnotizes her and learns via her connection with Dracula that he is sailing home in his last remaining box. The hunters depart for Varna to intercept him, but Dracula reads Mina's mind and evades them. Van Helsing and Mina travel to the Borgo Pass and the castle, while the other hunters try to stop the gypsies transporting Dracula. At night, Van Helsing and Mina are approached by Dracula's brides. Mina succumbs to their chanting and attempts to seduce Van Helsing. Before Mina can feed on his blood, Van Helsing places a communion wafer on her forehead, leaving a mark that slows her transformation. He surrounds them with a ring of fire to protect them from the brides, then kills the brides the following morning. Dracula's carriage arrives at the castle, pursued by the hunters. A fight between the hunters and Romani ensues. Morris is fatally stabbed in the back and Dracula bursts from his coffin at sunset. Jonathan slits his throat with a kukri knife while Morris stabs him in the heart with his knife. Van Helsing and Jonathan allow Mina to retreat with the Count while Morris dies in the arms of Seward, comforted by his friends. In the chapel where he renounced God, Dracula lies dying. He and Mina share a kiss as the candles adorning the chapel light up and the cross repairs itself. Dracula reverts to his younger self and asks Mina to give him peace. Mina thrusts the knife through his heart. As he dies, the mark on her forehead disappears, freeing her from his curse. She then decapitates him and gazes up at a fresco of Vlad and Elisabeta ascending to heaven together, finally reunited.

Late one evening, Allan Gray, a wandering student of the occult, arrives at an inn close to the village of Courtempierre, France, and rents a room. He is awakened from his sleep by an old man, who enters the locked room and leaves a small rectangular package on the table with "To be opened upon my death" written on the wrapping paper. Feeling drawn to investigate, Gray takes the package and leaves the inn. Gray follows the shadow of a soldier with a peg leg to a disused factory, where he sees the shadow reunite with its body, and witnesses other shadows dancing. He also sees an old woman who seems to hold sway over the shadows, and encounters an old man with a mustache, who shows Gray the door. Following some more shadows to a manor house, Gray looks through one of the windows and sees the lord of the manor, who is the man who gave him the package, get shot by the shadow of the soldier. Gray gets the attention of an old servant, and they rush to the lord of the manor, but it is too late to save him. Giséle, the lord of the manor's younger daughter, is there when he dies, but her sister, Léone, does not leave her bed, as she is gravely ill. A coachman is sent to get the police, and the old servant's wife invites Gray to stay the night. In the library, Gray opens the package and finds a book inside about horrific demons called vampires. As he begins to read about how the creatures suck blood and gain control over the living and dead, Giséle says she sees Léone walking outside. They follow her, and, when they catch up, see the old woman from the factory bent over Léone's unconscious body. The old woman slinks away, and Léone, who is discovered to have fresh bite wounds, is carried back to bed. The carriage returns, but the coachman is dead. The village doctor visits Léone at the manor, and Gray recognizes him as the old man with a mustache that he saw in the factory. The doctor tells Gray that Léone needs a blood transfusion, and Gray agrees to donate his blood. Exhausted from blood loss, Gray falls asleep. Meanwhile, the old servant has noticed the book and begun to read it. He learns that a vampire can be defeated by opening its grave at dawn and driving an iron bar through its heart, and that there are rumors that a vampire was really behind a previous epidemic in Courtempierre, with a woman named Marguerite Chopin being the prime suspect. Gray wakes up sensing danger and rushes to Léone's bedside, where he stops her from drinking poison that the old woman had the doctor bring to the manor. The doctor flees, kidnapping Giséle, and Gray follows. Just outside the factory, Gray trips and has an out-of-body experience, in which he sees himself dead, sealed in a coffin with a window, and carried away to be buried. After his spirit returns to his body, he notices the old servant heading to Marguerite Chopin's grave. They open the grave and find the old woman perfectly preserved, until they hammer a large metal bar through her heart, at which point she becomes a skeleton. The curse of the vampire is lifted, and, back at the manor, Léone suddenly recovers. The ghost of the lord of the manor appears to the doctor, causing him to run away and the soldier to fall to his death down a flight of stairs. Using information he gathered during his out-of-body experience, Gray finds and unties Giséle. The doctor tries to hide in an old mill, but the old servant, seemingly aided by an unseen force, locks the doctor in a chamber where flour sacks are filled and activates the mill's machinery, which fills the chamber with flour and suffocates the doctor. Giséle and Gray cross a foggy river in a boat and find themselves in a bright clearing.

An amorphous parasitic alien race abandons its dying planet and travels to Earth, taking the form of small seed pods with pink flowers upon settling. Elizabeth Driscoll, a laboratory scientist at the San Francisco Health Department, brings one of the flowers home, and shows it to her boyfriend, Geoffrey. She awakens the next morning to find him being cold and distant while putting debris of the glass that once held the flower pod into a garbage truck. Elizabeth confides to her colleague and friend Matthew Bennell about the unsettling changes in Geoffrey, and that she fears he is an impostor. Elizabeth mentions following him and seeing him secretly meeting with people she does not know. Matthew advises Elizabeth to talk to his psychiatrist friend David Kibner, to which she reluctantly agrees. On the way to Kibner, a hysterical man warns Elizabeth and Matthew of danger as a mob pursues him. The couple follows the mob, only to find his dead body surrounded by emotionless onlookers. At Kibner's book promotion event, Matthew finds his friend Jack Bellicec, an aspiring writer, while Elizabeth meets Kibner, who reassures a woman who claims that her husband has changed. Kibner brushes off both women's concerns, insisting the behavior is just a case of non-commitment. Elizabeth is convinced to return home to Geoffrey. Jack returns to the mud bath spa he runs with his wife Nancy. The two find a mysterious embryonic adult-body resembling Jack, and call Matthew to investigate. At the disturbing discovery, Matthew goes to warn Elizabeth, and discovers a semi-formed duplicate of her near her bedroom. Matthew rescues Elizabeth and alerts the police and Kibner about the events, but when they arrive, Jack and Elizabeth's duplicates have disappeared. Elizabeth suspects the flowers are involved, but is unable to examine one at the health department offices. In the meantime Matthew tries in vain to alert the authorities. After encountering several doppelgangers, Matthew, Elizabeth, Jack, and Nancy hide out in Matthew's apartment. They call Kibner, who promises to help, but in fact is another duplicate. As the group fall asleep, big flower pods emerge from the garden and start birthing their replacements. They wake up, and Matthew destroys his own replacement. The pod people (the fully formed alien replacements) pursue Matthew's group. Jack and Nancy create a distraction, sacrificing themselves, while Matthew and Elizabeth take refuge at the health department. They take speed to remain awake. Jack and Kibner's duplicates ambush and inject them with a sedative, needing them to fall asleep to be replaced. Kibner's duplicate explains the aliens' plan to replace humanity with emotionless duplicates whose only goal is survival. Matthew kills Jack's double and locks Kibner's in a freezer, then escapes with Elizabeth. Matthew and Elizabeth find Nancy, who tricked the pod people by hiding her emotions. The three blend in among the duplicates. Elizabeth sees a dog-human hybrid – a byproduct of a damaged pod – and screams, alerting the pod people who emit high-pitched screams. In the commotion, Matthew and Elizabeth are separated from Nancy. Boarding a truck delivering plants to Pier 70, they find pods grown and processed in a warehouse. Noticing a nearby ship, Matthew leaves Elizabeth (whose ankle is sprained) to investigate, only to find it being loaded with pods. Matthew returns to Elizabeth, finding her asleep. She disintegrates while her duplicate emerges from the grass. Matthew flees the duplicate, breaks into the dock warehouse, and burns down the building, destroying several plants and killing many pod people. He hides underneath the pier as pursuers search for him. A flashlight shines in his direction. Later, Matthew resumes work in the health department, acting emotionless among the duplicated employees. While outside, Nancy calls out to him. To her horror, he points at her and emits the duplicates' high-pitched scream.

In the 1890s, Ephraim Winslow begins a four-week stint as a "wickie" (lighthouse keeper) on an isolated island off the coast of New England, under the supervision of former sailor Thomas Wake. In his quarters, Winslow discovers a small scrimshaw of a mermaid and keeps it in his jacket. Wake immediately proves to be very demanding, subjecting Winslow to taxing jobs such as emptying chamber pots, maintaining the machinery, carrying heavy kerosene tanks up the stairs, and painting the lighthouse, while barring Winslow from the lantern room. Winslow observes that, every night after ascending the lighthouse, Wake disrobes before the light. During his stay on the island, Winslow begins to hallucinate sea monsters and logs floating in the sea, and masturbates to the mermaid on the scrimshaw. Winslow is bothered by a one-eyed gull, but Wake warns him against killing it under the superstitious belief that gulls are reincarnated sailors. One evening while dining, Wake reveals to Winslow that his previous wickie died after losing his sanity, while Winslow reveals that he is a former timberman from Maine who was stationed in Canada and is now seeking a new trade. The day before the scheduled departure, Winslow discovers a dead gull inside the cistern, bloodying the drinking water. He is attacked by the one-eyed gull and brutally bludgeons it to death. The wind drastically changes direction and a fierce storm hits the island. Winslow and Wake spend the night getting drunk, and the storm prevents the lighthouse tender from collecting them the next day. As Winslow empties the chamber pots, he discovers the beached body of a mermaid, which waves and howls at him. He flees back to the cottage, where Wake informs him the storm has spoiled their rations. Winslow is not worried because he thinks the tender is only a day late, but Wake says that they have already been stranded for weeks. The pair unearths a crate at the lighthouse's base that Winslow assumes contains reserve rations, but it is full of bottles of alcohol. As the storm continues to rage, Winslow and Wake get drunk every night and alternate between moments of intimacy and hostility. One night, Winslow tries unsuccessfully to steal the lantern room keys from Wake and contemplates murdering him. Winslow later sees the one-eyed head of Wake's previous wickie in a lobster trap. While drunk, Winslow confesses to Wake that his real name is Thomas Howard, and he assumed the identity of Ephraim Winslow, his cruel foreman in Canada whom he deliberately allowed to drown during a log drive. Howard has a menacing vision of Wake accusing Howard of "spilling beans" and runs to the dory to try to leave the island, but Wake appears and destroys the boat with an axe. After chasing Howard back to their lodgings, Wake claims it was Howard who chased him and hacked up the dory, as Howard was driven mad by his confession. With no alcohol left, Howard and Wake begin drinking a concoction of turpentine and honey, and that night a giant wave crashes through the wall of their cottage. In the morning, Howard finds Wake's logbook, in which Wake has criticized him as a drunken and incompetent employee and recommended he be fired without pay. The two men argue, and Howard attacks Wake while hallucinating the mermaid, the real Winslow, and Wake as a Proteus -like figure. Howard beats Wake into submission and takes him to the hole at the base of the lighthouse to bury him alive. Before losing consciousness, Wake describes a " Promethean " punishment that awaits those who look in the lantern, and Howard takes the keys to the lantern room. Howard goes to get a cigarette, and Wake returns and strikes him with the axe. Howard disarms and kills Wake before ascending the lighthouse. In the lantern room, the Fresnel lens opens to Howard, who reaches in and violently screams in distortion before falling down the lighthouse steps. Some time later, a barely-alive Howard lies nude on the rocks with a damaged eye as a flock of gulls peck at his exposed organs; the lighthouse is nowhere in sight.

A mysterious Japanese man arrives in Gokseong, a small village in the mountains of South Korea. Soon after, a bizarre infection breaks out, causing villagers to become deranged and violently kill their families. Officer Jong-goo's daughter, Hyo-jin, becomes one of the infected. Jong-goo then meets a mysterious young woman named Moo-myeong, who claims the Japanese stranger is an evil spirit. A local hunter reports seeing the stranger with glowing red eyes eating a deer carcass. After a series of disturbing events and violent deaths, Jong-goo enlists the help of a Japanese-speaking deacon, Yang I-sam. They investigate the stranger's house, discovering a shrine with photos and belongings of the murdered villagers, including Hyo-jin's shoe. As Hyo-jin's condition worsens, Jong-goo confronts the stranger, ordering him to leave the village. Jong-goo's family discovers a dead goat hanging at their gate, and Hyo-jin stabs their neighbor to death. A shaman named Il-gwang is consulted, who claims the stranger is a demon and performs a death-hex ritual. Jong-goo stops the ritual midway, instead taking Hyo-jin to the hospital. The next day, Jong-goo and his companions hunt down the stranger but are attacked by the reanimated corpse of another victim, giving the stranger time to flee. They eventually kill him, and Hyo-jin's health improves. Il-gwang encounters Moo-myeong and vomits blood. After his ritual fails, he leaves town in terror but a swarm of flying insects stops him. He calls Jong-goo, warning that Moo-myeong is the real demon, and the stranger was a shaman who was trying to kill her. Meanwhile, Yang I-sam receives news that his uncle Oh Seong-bok has killed his family. Jong-goo goes home and finds that Hyo-jin has disappeared. While looking for Hyo-Jin, Jong-goo runs into Moo-myeong, who he confronts about Hyo-jin's whereabouts. Moo-myeong claims his daughter is possessed by the stranger, who is consuming her life force. She also tells him his daughter is still alive, has just returned and will kill his family. She reveals that she has set a trap for the demon, and that all Jong-goo has to do is remain there and wait. Jong-goo replies that he is not sure if he believes her. The shaman phones him and says he must not let Moo-myeong tempt him. Moo-myeong instructs him to simply wait until the third crow of the rooster. Meanwhile, Hyo-jin returns home possessed and while eating with her hands, eyes a knife in the kitchen. While Jong-goo is engaged with Moo-myeong, Yang I-sam returns to the stranger's house armed with a sickle and finds him alive inside a cave. Yang promises to leave if the stranger reveals his true form. The stranger chuckles at this. Jong-goo notices Moo-myeong is wearing items of the victims and sees his daughter's hairpin on the ground. Believing this to be proof that she is responsible for the infection, he returns home before the rooster's third crow. Upon returning home, Jong-goo discovers that Hyo-jin has slaughtered his wife and mother-in-law; she then attacks him. Meanwhile, the stranger repeatedly photographs Yang I-sam. He then assumes his true appearance—that of a red-eyed demon, bearing stigmata. Il-gwang returns with a camera in his hand and finds Jong-goo's dead family as Hyo-jin sits in a trance and Jong-goo lies dying. Il-gwang photographs the dead family members, then returns to his car and retrieves a box which he drops, revealing photos of other families and victims of the demon. Jong-goo reminisces about the happy times with his daughter as he dies.

Struggling inventor Randall Peltzer visits a Chinatown antique store to find a Christmas present for his son, Billy. In it, Randall uncovers a small and furry creature called a mogwai (Cantonese: 魔怪, 'devil'). The owner, Mr. Wing, refuses to sell it to him, but his grandson secretly does, warning Randall to remember three important rules concerning its care – keep the creature away from light, especially sunlight, which will kill it; do not let it come in contact with water; and above all, never let it eat after midnight. In Randall's hometown of Kingston Falls, Billy works at its local bank, but fears that his dog Barney will be put down by widowed miser Ruby Deagle. His father returns and offers him the mogwai, now named "Gizmo", as a pet and informs him of the rules. Gizmo is friendly and docile, but when Billy's friend, Pete Fountaine, accidentally spills water on him, five more mogwai spawn from him – a more mischievous sort led by the aggressive Stripe, named after the mohawk -like tuft of white fur on his head. Billy shows one of the mogwai to his former elementary school science teacher, Roy Hanson, spawning another mogwai, whom the latter experiments on. Back home, Stripe and his fellow mogwai trick Billy into feeding them after midnight by sabotaging his bedside clock. They form cocoons, as does Hanson's mogwai, which soon hatch, emerging as destructive and reptilian imp-like monsters called "gremlins". Hanson is murdered by his gremlin, while those at the Peltzer house torture Gizmo and assault Billy's mother, Lynn. The duo are able to dispatch all the gremlins sans Stripe, who escapes to the local YMCA where he jumps into its swimming pool, spawning an army of gremlins that wreak havoc on Kingston Falls. Many locals are injured or outright killed during their rampage, including Deagle. The police are helpless in the ordeal, as they too fall victim to the gremlins' mischief. After Billy rescues his co-worker and girlfriend, Kate Beringer, when the gremlins attack the bar she works at, and they seek refuge in the bank, the latter discloses that her father went missing on Christmas Eve when she was nine years old, but was then found dead in their house's chimney several days later. Planning to surprise his family while portraying Santa Claus, he inadvertently slipped and broke his neck while climbing down the chimney. Still suffering from post-traumatic stress disorder due to the incident, Kate confesses how this led to her dislike of the holidays. The trio find the gremlins gathered in the local movie theater due to morning approaching and set off a natural gas explosion, killing them all except for Stripe, who left the theater earlier to retrieve candy at a Montgomery Ward store across the street. They follow Stripe into the store, where he attempts to use a fountain to spawn more gremlins, but Gizmo then opens a nearby skylight, exposing Stripe to sunlight and killing him. In the aftermath, Mr. Wing arrives at the Peltzer house to reclaim Gizmo as he scolds the family for their negligence and criticizes Western society for its carelessness with nature. However, as he turns to leave, Gizmo, having bonded with Billy, bids him goodbye. A compassionate Wing then concedes that Billy may be ready to properly care for him one day.

Unemployed number theorist Max Cohen, who lives in a drab apartment in Chinatown, Manhattan, believes everything in nature can be understood through numbers. He suffers from cluster headaches, extreme paranoia, hallucinations, and schizoid personality disorder. His only social interactions are with his mathematics mentor, Sol Robeson (now disabled from a stroke), and those who live in his building: Jenna, a little girl fascinated by his ability to perform complex calculations, and Devi, a young woman living next door who sometimes speaks with him. Max tries to program his computer, named Euclid, to make stock predictions. Euclid malfunctions, printing out a seemingly random 216-digit number, as well as a single stock pick at one-tenth its current value, then crashes. Disgusted, Max throws away the printout. The next morning, he learns that Euclid's pick was accurate but cannot find the printout. When Max mentions the number, Sol becomes unnerved and asks if it contained 216 digits. He reveals that he came across the same number years ago and urges Max to take a break from his work. Max meets Lenny Meyer, a Hasidic Jew who does mathematical research on the Torah. Lenny demonstrates some simple Gematria, the correspondence of the Hebrew alphabet to numbers, and explains that some people believe the Torah is a string of numbers forming a code sent by God. Intrigued, Max notes that some of the concepts parallel other mathematical concepts, such as the Fibonacci sequence. Agents of a Wall Street firm approach Max. One of them, Marcy Dawson, offers him a classified computer chip called "Ming Mecca" in exchange for the results of his work. Using the chip, Max has Euclid analyze mathematical patterns in the Torah. Once again, Euclid displays the 216-digit number before crashing. As Max writes down the number, he realizes that he knows the pattern, undergoes an epiphany, and loses consciousness. After waking up, Max appears to become clairvoyant and visualizes the stock market patterns he sought. His headaches intensify, and he discovers a vein-like bulge protruding from his right temple. Max has a falling-out with Sol after Sol urges him to quit his work. Dawson and her agents grab Max on the street and try to force him to explain the number, having found the printout Max threw away. Attempting to use the number to manipulate the stock market, the firm instead caused the market to crash. Driving by, Lenny rescues Max, but takes him to his companions at a nearby synagogue. They ask Max to give them the 216-digit number, believing it was meant for them to bring about the Messianic Age, as the number represents the unspeakable name of God. Max refuses, insisting the number has been revealed to him alone. Max flees and visits Sol, only to learn from his daughter, Jenny, that he died from another stroke. He finds a piece of paper with the number in his study. At his own apartment, Max experiences another headache but does not take his painkillers. Believing the number and the headaches are linked, Max tries to concentrate on the number through his pain. After passing out, Max goes to the bathroom where he stares at himself in the mirror before lighting a match and burning the piece of paper with the number. Max then takes a power drill to his own head, trepanning himself in an effort to find relief. Sometime later, Jenna approaches Max in a park and asks him to do several calculations, including 748 ÷ 238 (an approximation for pi). Max smiles and says that he does not know the answer, seemingly at peace.

Henry Spencer's face appears superimposed over a planet in space. He opens his mouth and a spermatozoon -like creature emerges. A man inside the planet moves a set of levers, and the creature is flushed away. In an industrial cityscape, Henry walks home with his groceries. He is stopped outside his apartment by a woman across the hall, who informs him that his girlfriend, Mary, has invited him to dinner with her family. Henry leaves his groceries in his apartment, which is filled with piles of dirt and dead plants. That night, Henry visits Mary's home, conversing awkwardly with her mother. At the dinner table, he is asked to carve a Cornish game hen; the bird moves and writhes on the plate and gushes blood when cut. After dinner, Henry is cornered by Mary's mother, who tries to kiss him. She tells him that Mary has had his child and that the two must wed. This causes Henry to have a nose bleed. However, Mary is not sure if what she bore is a child. The couple moves into Henry's one-room apartment and begins caring for the child, a swaddled bundle with an inhuman face that resembles the spermatozoon creature seen earlier. The infant refuses all food and cries incessantly and intolerably. The sound drives Mary hysterical, and she leaves Henry and the child. Henry attempts to care for the child, and he learns that it struggles to breathe and has developed painful sores on its skin. Henry begins experiencing visions, again seeing the man in the planet, as well as a lady who inhabits his radiator and stomps more of the sperm creatures. After a sexual encounter with the girl across the hall, he has another vision in which the lady in the radiator sings (" In Heaven "), and his head pops off his body while he is fidgeting, replaced by the baby's crying head. Henry's disembodied head falls from the sky, landing on a street and breaking open. A boy finds it and takes it to a pencil factory to be turned into erasers. Awakened, Henry seeks out the girl across the hall, but finds her with another man. Crushed, Henry returns to his room. He takes a pair of scissors and for the first time removes the child's swaddling clothes. It is revealed that the child has no skin; the bandages held its internal organs together, which proceed to spill out after the bandages are cut. The child gasps in pain, and Henry stabs its organs with the scissors. The wounds gush a thick liquid, covering the child. The power in the room overloads, causing the lights to flicker; as they flick on and off the child grows to huge proportions. As the lights burn out completely, the child's head is replaced by the planet seen at the beginning. Henry appears amidst a billowing cloud of eraser shavings. The side of the planet bursts apart and the man inside struggles with his levers, which emit sparks. Henry is embraced warmly by the lady in the radiator in a white void.