The movie begins with a woman hearing a phone ring at a subway train and goes to the public phone booth to answer it. She hears nothing at first until high pitched beeping sounds slowly climb up, which makes the woman shake vibrantly and make her eyes bleed and is then thrown onto the escalator due to the explosion that sounded like thunder. Nat Bridger, an ecology professor, goes to the Thorner home after teaching his class. Thorner and his wife can't handle the fact that their daughter, Sandra, is dead (the woman from the opening scene) after her murder. Later that night, a businessman, Gordon Smith is later electrocuted by the phone he was using when it ringed and was thrown out through the large glass window and crashes onto a car and was killed. The next day, Nat goes for a ceremony and gets called for the letter of authorization to send to the caller. He goes to see Lt. Merra when he finds out that Sandra's death was caused for a heart attack. Then Nat stays over at Stanley Markowitz place and interviews a lady who had witnessed the murder. Later that night, Mrs. Andersen gets killed by the phone. Nat tries to figure out why the phone at the subway was repaired and gets rejected at first then gets to talk to the supervisor at a business industry. He met Ridley Taylor inside not so long ago after a talk with the supervisor and invites her to dinner. And another phone gone wrong happened at Connie Lawson and was killed. Later the next day, Nat gets into an argument with Meara for not helping him on the case. Nat gets followed by a tourist guy who takes pictures and thinks he's working for someone but gets pulled away. After being arrested and healed by Stanley, Nat goes to the phone control center to search for evidence that can led to the mystery and finds pairs of phones that were used for the murders. After Nat has arrived at Ridley's house, Stanley gets murdered by the phone. Nat and Meara go to the commissioner about Stanley's discussion on the phone murders and gets called out. Nat goes to Stanley's house for evidence until he realizes that from the video tape player, an address that led to Ridley's house and plays the tape at Ridley's house realizing that Noah Clayton, the tour guide, must be the phone operator, killing people by the use of a phone. After Nat leaves, Ridley gets a phone call from Noah and before he can kill her through the phone, Ridley throws it away, not getting killed. Nat and other men, along with Ridley, go to the Power company for clues and Nat gets the phone call from Clayton, revealing his innovations for killing people through phones for revenge over perceived injustices. Before he kills Nat, the deadly high-frequency sonic pulse he designed for his telephone murders is reversed and sent back through the line, causing Clayton to convulse and a shelf behind him falls on him and is killed. The movie ends with the whole mystery solved and Nat gets a call from Al Histlip, the public safety department of the city, congrates him for solving the phone murders and as Ridley leaves to go home, Nat calls out "I'll call you" before the high pitch beeping noises come again and the movie cuts out to the credits.

Dawn O'Keefe is a teenage spokesperson for a Christian abstinence group, "The Promise". She frequently overhears her stepbrother Brad and his girlfriend Melanie arguing about his refusal to engage in vaginal intercourse, insisting on only having anal sex. One afternoon at a group meeting, Dawn is introduced to Tobey. Dawn, her friends Gwen and Phil, and Tobey begin going out as a group. Though Dawn and Tobey are attracted to each other, they initially agree they should not spend time alone together. However, they later give in and meet at a local swimming hole. After their swim, they enter a cave to get warm and begin kissing. Dawn becomes uncomfortable and tries to persuade Tobey to go back outside, but he becomes aggressive. When Dawn tries to push him off, he shakes her, smacking her head on the ground and dazing her. As Tobey attempts to rape her, but her vagina 'cuts' Toby's penis as it enters vagina, causing him to bleed and fall down the waters and die. A horrified Dawn flees the scene. After a Promise meeting, Dawn runs into her classmate Ryan at a dance. He drops her off at her home and asks her out on a date, but she declines. Dawn returns to the swimming hole and screams in horror when she sees a crab crawling on Tobey's severed penis. She drops her purity ring off a cliff. She then researches vagina dentata and realizes she may have it. She visits a gynecologist, Dr. Godfrey, but he assaults her during the examination, reaching up inside her without a glove. She panics and her vagina bites off four fingers on his right hand. On her way home, she sees several police vehicles passing her, as well as a car that resembles Tobey's. That evening, she returns to the pool to investigate. When she arrives, the police are bringing up Tobey's body. Dawn returns home to find her ailing mother, Kim, unconscious on the floor while Brad and Melanie are in his room having sex. Kim is taken to the hospital. Hysterical, Dawn goes to Ryan seeking help. Ryan gives her a sedative and stimulates her with a vibrator. Though initially afraid she will hurt him, she finds that when she is relaxed and consenting, her "teeth" do not engage. The following morning, they have sex again, but during intercourse, Ryan's friend calls. Ryan smugly boasts that he had made a bet with the friend that he could goad Dawn into sex. In her anger, her vagina bites off his penis and she leaves as he screams in agony. Dawn's stepfather Bill attempts to throw Brad out of the house, but Brad sets his pet Rottweiler on Bill, confessing his love for Dawn. Dawn meets Bill and Melanie at the hospital after her mother has died. Seeing her stepfather injured and hearing from Melanie how Brad told her to ignore her mother's cries for help, Dawn becomes emboldened by her power and goes home to seek revenge. She applies make-up and goes to Brad's room to seduce him. In the midst of the act, Brad recalls that when they were children, Dawn bit his finger, but it was not her mouth that bit him. As he realizes this, Dawn's vagina bites off his penis. She drops it on the ground and although Brad calls his dog to attack her, the animal instead eats the penis, spitting out the pierced glans. Dawn leaves despite his pleas for her to stay. Dawn cycles away from home, but her bicycle tire sustains a puncture, prompting her to hitchhike. She accepts a lift from an old man but falls asleep and wakes up after nightfall outside a convenience store. When she tries to exit his car, he repeatedly locks the doors while licking his lips. Dawn hesitates, then turns to the old man with a mischievous smile.

On June 19, 1987, as the Earth crosses the tail of a rogue comet, Rhea-M, previously inanimate machines spring to life; an ATM insults a customer (Stephen King) and a bascule bridge rises during heavy traffic, causing all vehicles upon the bridge to fall into the river or collide. Chaos sets in as machines begin attacking humans worldwide automatically. At the Dixie Boy Truck Stop outside Wilmington, North Carolina, employee Duncan Keller is blinded after a gas pump sprays diesel in his eyes. After an electric knife injures waitress Wanda June and arcade machines in the back room electrocute a customer, cook and paroled ex-convict Bill Robinson begins to suspect foul play. Meanwhile, at a Little League game, a vending machine kills the coach by firing canned soda at him. A driverless road roller flattens a fleeing child, while Duncan's son Deke escapes on his bike. Newlyweds Connie and Curtis discover a corpse at a roadside gas station, but escape in their car when a tow truck attempts to kill Curtis. Meanwhile, humans and pets are murdered by lawnmowers, chainsaws, electric hair dryers, pocket radios, RC cars and an ice cream truck. At the Dixie Boy, a garbage truck kills Duncan when he departs to search for Deke, and a truck sporting a giant fiberglass Green Goblin mask on its grille slams bible salesman Camp Loman into a ditch. Later, big rig trucks encircle the truck stop. Connie and Curtis outmaneuver a semi-truck, causing it to crash off the side of the road and explode. They arrive at the fortified truck stop, where it is safer than out in the open. As they try to pass between the trucks, their car is hit and overturned. Bill and hitchhiker Brett Graham rush to help them before the trucks attack. The owner Bubba Hendershot uses M72 LAW rockets he had stored in a bunker hidden under the diner to destroy many of the trucks. Deke later arrives at the Dixie Boy and attempts entrance via the sewers, but is obstructed by the wire mesh covering the opening. That night, the survivors hear Loman screaming, and Bill and Curtis sneak out via the sewers to help him. Deke discovers Loman, believing him dead, but he awakens and attacks Deke. Bill and Curtis rescue Deke and determine that Loman is indeed dead, but a truck then chases them back into the pipe. The next morning, a bulldozer and a platform truck drive to the truck stop. The angered Hendershot uses the rocket launcher to blow up the bulldozer but only succeeds in blowing its roof off, but the platform truck fires its post-mounted machine gun into the building, killing many including him and Wanda. The truck then demands, via sending morse code signals through its horn that Deke deciphers, that the humans pump the trucks' diesel for them in exchange for their lives. As the survivors realize that their own machines have enslaved them, Bill suggests that they escape to Haven, an island off the coast, on which no motorized vehicles are permitted. While the crew rests, Bill theorizes that the comet is actually a "broom" operated by interstellar aliens that are using Earth's machines to destroy humanity so the aliens can repopulate the Earth. The next day, during a fueling operation, Bill sneaks a grenade onto the platform truck, destroying it, then leads the party out of the diner via a sewer hatch to the main road just as the trucks and the bulldozer demolish the entire building. As the remaining people approach the marina, the ice cream truck appears, but Brett and Curtis open fire and destroy it. The Green Goblin truck stalks them to the marina and kills Brad, a trucker distracted by a diamond ring on a corpse's finger. After Bill destroys it with a hit from a rocket shot, the survivors board a sailboat and set sail for Haven. Two days later, the machines go silent when a UFO hiding in the comet's tail is destroyed by a Soviet space platform disguised as a weather satellite, equipped with nuclear missiles and a laser cannon. Six days later, Earth passes out of the comet's tail, and the survivors are still alive.

James is a video archivist working for a local television station, and still grieving the mysterious disappearance of his wife named Hannah three years earlier, James buries himself in work, spending his nights digitizing old broadcast tapes. One evening, while reviewing footage, he discovers a strange and disturbing broadcast signal intrusion, a pirate video interrupting regular programming. The clip shows a person wearing a distorted white rubber mask and speaking in a garbled, unintelligible voice. The strange visuals creep James out, stirring something deep and uncomfortable inside him. Curious and increasingly obsessed, James begins researching the origin of the intrusion. He discovers that similar broadcast signal intrusions occurred in late 1987 and the early 1990s, all unsolved. Even more disturbing, these incidents seem to coincide with the disappearances of several women, one of whom bears a strong resemblance to Hannah. This connection deepens James's fixation, and what begins as a curiosity quickly turns into a personal mission. His investigation leads him to a range of eccentric and secretive figures, and he contacts a former FCC investigator named Dr. Stuart Lithgow. As James pieces together clues, he starts to believe that the videos were created by someone attempting to send a message or expose a sinister truth possibly about a group known as the "Nite Pirates" who were rumored to be behind some of the original intrusions. Stuart dismisses James's investigation, saying the case had already been abandoned and was too difficult to solve. In the night, he meets Alice, a mysterious young woman with her own troubled past, who becomes a temporary companion in his search for answers. Together, they follow a trail of clues hidden within the footage, including Morse code, odd audio signals, and phone numbers embedded in the video. As James digs deeper, his grip on reality begins to fray. He becomes paranoid, convinced he's being followed, and begins seeing hallucinations of masked figures from the tapes. Alice eventually disappears without a trace, leaving James further isolated. His quest becomes more dangerous as he tracks down the location believed to be the source of the third tape, a previously unknown intrusion video of an abandoned farmhouse. Inside the farmhouse, James finds a man named Michael Gardiner, who appears to be mentally unstable and possibly connected to the broadcast intrusions. James is now fully consumed by his obsession and had planned to rebuild the hijack setting that Michael used during his crime. Restraining him, Michael forces him to reenact the original broadcast hijacked setting, dressing him in the same mask that he used on the victims and demanding a confession. Whether Michael is truly guilty remains ambiguous, but James kills him, convinced that he has found the person responsible for both the videos and perhaps even his wife's disappearance. On the drive back to the city, James begins to hallucinate more intensely. He sees and hears broadcast interference in his car's radio, but suddenly, he hits something on the road - a young woman standing in the dark - and he investigates, her face appearing artificial, almost robotic, with black liquid oozing from her mouth.

The film takes place in Antarctica, centering around a rescue team that is sent to the Routledge research station to investigate a research team's lack of communication with the outside world. Once there, the team discovers no survivors in the research station but finds a diary that describes the research team's last days. The diary goes over the research team's growing malcontent and paranoia as the team is picked off one by one by a mysterious killer.

The film begins with the alien abduction on Scalleum, a remote island off the coast of Wales, of Cat Williams and her boyfriend. Cat's boyfriend is gorily killed through brutal anal probing, and Cat is (also gorily) implanted with an alien fetus. Cat's story attracts the attention of Michelle "Foxy" Fox, the bosomy host of the cable TV show Weird Worlde, who brings a film crew to the island — her cameraman boyfriend Ricky; Jack the sound man; nerdy UFO expert Gavin Gorman; and actors Bruce Barton and Candy Vixen (the latter, Foxy's producer assures her, "because she's good, not because she's my girlfriend"). The island is accessible via a narrow causeway only at low tide. The Weird Worlde crew sets out in their van, but it is dark by the time they reach the Williams family's creepy farmhouse, where they meet Cat and her three hulking and sadistic brothers (who speak only Welsh with English subtitles). The crew (with the exception of Gavin Gorman) initially assume that Cat's story is a hoax, and even go so far as to make a crop circle in a nearby field so they can film it for the show, to Gorman's great disgust. However, it soon turns out that the aliens are all too real and rather malevolent. The film crew teams up with the Welsh Williams brothers to fight off the aliens, with a great deal of blood and gore. One highlight features Ricky running down some aliens in a combine harvester, to the tune of " Combine Harvester (Brand New Key) " by The Wurzels. Eventually, the alien child inside Cat claws its way out; on board the alien ship, Foxy is impregnated with another alien fetus while Gavin loses his virginity to a shapely female alien; Bruce, Candy, and the Welsh brothers meet various horrible demises; Ricky blows up himself and four alien pursuers in a tank of liquid manure; back at the house, the female alien rips Foxy in half; and finally Gavin manages to use his laptop (in a sequence reminiscent of Independence Day) to overload the ley lines of the nearby stone circle. As Cat's alien child rips his arms off, Gavin manages to press the space bar with his nose, sending the stones shooting into the underside of the alien craft, which crashes into a convenient mountain. Jack the sound man, meanwhile, having been blinded by alien ichor early in the film, swims across the channel to the mainland, only to discover that he's lost the videotape that was the only proof of their extraterrestrial encounter. The film ends with a clip from an alien talk show reminiscent of Jerry Springer (and subtitled in English), on which Gavin's female alien is trying to explain how her entire crew was killed by humans and she herself carries the love child of one of those humans. The audience roars with laughter, and the host cuts her mike.

Two years after the Apollo 17 mission, the crew of the cancelled Apollo 18 mission consisting of Commander Nathan Walker, Lieutenant Colonel John Grey, and Captain Ben Anderson are informed that it will proceed as a top-secret Department of Defense (DoD) mission to place an early warning detector on the Moon for ICBM attacks from the USSR. Grey remains aboard Apollo command module Freedom while Walker and Anderson land in Apollo Lunar Module Liberty to plant the detector. Anderson takes back rock samples and the two return to Liberty. The samples cause small disturbances, which Houston attributes to interference from the detector. The next day, Anderson discovers footprints that lead them to an abandoned but functioning Soviet LK lander. They discover a crater with a dead cosmonaut, to which Houston dismisses Walker's queries. While sleeping, Walker is awakened by strange noises and an object bumping into the lander. Walker and Anderson complete the mission and prepare to leave, but the launch is aborted when Liberty suffers violent shaking, which they discover is a result of damaged foil. Nearby, they find non-human tracks outside the Liberty alongside damaged equipment. Walker is horrified at a spider-like creature that has entered his spacesuit and disappears before Anderson finds him unconscious near Liberty, which Walker later denies happening. Later, Anderson removes a Moon rock embedded in Walker. Walker smashes the rock, contaminating the ship. Due to interference from an unknown source, the two are unable to contact Houston or Grey. Anderson speculates that the device is meant to monitor the aliens and that it is the source of the interference. They attempt to deactivate the device but find it destroyed. Walker begins to become contentious and paranoid, and they discover that the aliens are camouflaged as Moon rocks. In an attempt to destroy the cameras inside Liberty, Walker destroys other controls, causing the ship to depressurize. While traveling to the Soviet LK lander to get oxygen, Walker intentionally crashes the rover, believing that he will spread the infection on Earth if he were to return. Anderson awakens and finds Walker getting pulled into a crater by the aliens. Anderson fails to rescue him and flees to the Soviet LK. He uses the radio to contact the USSR Mission Control, who connect him to the DoD. The Deputy Secretary informs Anderson that they cannot allow him to return to Earth, admitting that they are aware of the situation and incorrectly believe that he is also infected. Grey contacts Anderson, and they plan to return him to Freedom. As Anderson prepares to launch, Walker suddenly appears and demands to be let in before being suddenly swarmed by the aliens, who kill him. Anderson launches, but the DoD informs Grey that he is to abort the rescue, or they will not allow him to return either. The LK enters orbit and, while in free fall, the aliens attack and infect Anderson. Anderson is unable to control the ship, and he collides with Freedom. The U.S. government states that the astronauts were killed in various jet accidents that left their bodies unrecoverable. They note that many of the rock samples returned from previous Apollo missions given to dignitaries are now missing.

Archie Andrews, a kindergarten teacher and vegan, regularly buys products from Lorraine's vegetarian roadside stand. He is developing an engine powered by wheatgrass, but his experiments prove unsuccessful until he accidentally cuts his finger and blood drips into the wheatgrass. After the mixture reaches the engine, it begins to operate successfully. Archie tests the vehicle and offers a ride to Denise, the owner of a meat stand and Lorraine's business rival. After Denise shows interest in Archie he drives her home but runs out of fuel. Seeking an alternative source of blood, Archie turns to hunting animals; however, their blood supply proves insufficient. He then targets larger prey, then violent criminals, before eventually killing people indiscriminately. The government, having monitored Archie's progress, approaches him after the original Blood Car is destroyed. Federal agents offer him any position he desires in exchange for helping produce additional Blood Cars and agreeing to the erasure of his former identity. When Archie questions the source of fuel for the new vehicles, the agents explain that it will be obtained from people with disabilities, convicted criminals, and homeless people. Archie accepts the offer. The film concludes with images of his rise to the presidency intercut with scenes of government agents murdering Lorraine, Denise, Archie's kindergarten students, and other individuals connected to the development of the Blood Car.

The film begins with a video documentary by Dr. David Kruipen (Val Kilmer), a research scientist on Banks Island, in the Canadian Arctic and the outbreak of a pandemic, with 400 dead and 10,000 infected. This is followed by a flashback to when David, his assistant Jane (Anne Marie DeLuise) and two other researchers tranquilize a polar bear, then discover the frozen remains of a woolly mammoth. They transport the polar bear to their research station. David calls his daughter Evelyn (Martha MacIsaac) and pleads with her to visit the research station. Their relationship has been strained since the recent death of her mother. Meanwhile, a group of students, Ling (Steph Song), Federico (Kyle Schmid) and Atom (Aaron Ashmore), are selected to join David's research team; Evelyn decides to come. Days later, David's research team begins feeling the effects of a strange illness, and David tells helicopter pilot Bart not to bring his daughter Evelyn to the station. However, Evelyn insists, leaving Bart no choice but to bring her to the station along with the students. In the meantime, Jane shoots and apparently kills David and another researcher. The students discover the body of the polar bear, and Bart is bitten by a bug while touching it. Evelyn is awakened in the middle of the night by an all-terrain vehicle approaching the station. When Evelyn investigates, she discovers Jane in the helicopter. Jane has destroyed the helicopter's control panel, eliminating any immediate chance of escape. Ling wakes up with many bug bites on her face and torso, and Jane dies in Evelyn's arms. Realizing Ling is sick, Federico calls in a helicopter to rescue Ling. Attempting to find David, Evelyn and Atom discover eggs in the brain of the mammoth. Assuming her father has been infected, Evelyn and Atom deduce that something has made the group sick. Evelyn decides to cancel the rescue helicopter and quarantine the group until a better-prepared team can rescue them. Federico, discovering he too is infected, goes berserk and destroys the radio. The bite on Bart's arm is infected and he has Atom and Evelyn amputate his arm at the elbow. The group decides to destroy the facility and wait things out in the helicopter. Ling is attacked by bugs who have made their way in through the ventilation system. Bart discovers that the amputation was useless as his upper arm is now showing signs of infection; he opts to stay behind with Ling. They deliberately overdose on morphine and fall asleep as the bugs swarm over them. Federico comes running out, refusing to be checked for infection, then turns on Evelyn and Atom. As he is about to shoot Evelyn, he is shot from behind by David. David insists they destroy the research station. Evelyn finds a video David recorded and discovers that David has intentionally infected himself, preparing to set the bugs loose to teach humanity a lesson about global warming 's effects. As a rescue helicopter comes to pick up David, Evelyn and Atom are locked up by David, but they escape. Atom grabs one of the helicopter’s skids to attempt to make the helicopter land, but falls to the ground after being shaken off by the pilot’s attempts to stabilise it, and is mortally injured. As the helicopter starts flying away, Evelyn shoots at it, causing it to crash into a building previously doused in gasoline. David and the helicopter crew die in the resulting fire; Evelyn finds Atom, who dies in her arms. The following day another rescue team arrives, finding the destruction and Evelyn, the sole survivor. Later, as a radio station airs information based on Evelyn's reports, a hunter calls his dog away from a dead bird the dog has been eating. Bugs emerge from the bird's body, which was infected from eating the mammoth. The closing scene shows the hunter's truck heading towards a large city.

Akademik Vladislav Volkov, a Russian research vessel in the South Pacific, communicates with the orbiting space station Mir. An energy source traveling through space strikes Mir, killing the cosmonauts and beaming itself down to Volkov. The electrical surge takes over the ship and attacks the crew. Seven days later, the tugboat Sea Star, captained by alcoholic Robert Everton, loses its uninsured cargo while sailing through a typhoon. Sea Star 's crew discover the engine room taking on water. When Sea Star takes refuge in the eye of the storm to make repairs, Volkov appears on their radar. Realizing that it could be worth millions in salvage, Everton orders his crew aboard. On Volkov, most of the electronics have been destroyed and the Russian crew are seemingly missing. Everton orders Sea Star 's navigator and ex- Navy officer Kelly Foster to help a fellow crewman, Squeaky, restore power to the ship. The ship's anchor then drops on its own, sinking Sea Star with deckhand Hiko and first mate J.W. Woods Jr. on board. Sea Star 's engineer Steve Baker leaves Squeaky to guard the engine room, where a robotic creature lures him to his death. Steve rescues an injured Hiko, while Woods comes out unscathed. As Foster treats Hiko in the sick bay, Chief Science Officer Nadia Vinogradova, the sole surviving member of Volkov 's crew, shoots at the crew before Steve subdues her. Nadia is hysterical about "it" needing power to travel through the ship and implores the crew to shut down the generators. She attacks Everton and Foster, who subdue her and take her to the bridge. Steve, Woods, and crewman Richie Mason look for Squeaky in the engine room but instead stumble upon an automated workshop producing more robots. The three are attacked by the robots and what appears to be a gun-wielding Russian crew member. The Russian is revealed to be a cyborg, but the three bring it down with salvaged munitions from Volkov 's small arms locker and take its seemingly dead body to the bridge. Nadia explains that the sentient electrical energy beamed from the Mir took over the ship eight days prior, scanned the ship's computers to find information on killing humans, then used the automated workshops to convert Volkov' s crew into cyborgs; the one brought to the bridge was the ship's captain and Nadia's husband. As the storm resumes, the crew head for the computer room. En route, they are ambushed by a converted Squeaky and a giant robot that kills Woods. The survivors barricade themselves in the communications room. Richie sends out a mayday, but Everton shoots out the radio, unwilling to give up his salvage. Foster punches Everton and removes him from command. Richie uses the computers to talk to the alien; it says that it is "aware" and sees mankind as a "virus" which it plans to use as "spare parts." This drives Richie insane, causing him to gun down Squeaky and flee. When the remaining crew leave the room, Everton talks to the alien, which recognizes him as the "dominant lifeform." The crew discovers that the alien has moved Volkov ' s computer elsewhere in the ship. Realizing that Volkov is moving, they return to the bridge by going outside, where Hiko is lost to the typhoon. Meanwhile, Everton is guided to one of the workshops, where he makes a bargain with the alien. Foster identifies Lord Howe Island as Volkov' s destination, with Nadia surmising that the alien wishes to seize a British intelligence station from which it could seize control of the world's military forces. As they decide to sink Volkov, the survivors are confronted by the now-cyborg Everton, which they defeat with a thermite hand grenade. They empty Volkov 's fuel tanks and set explosive charges. Foster, Steve and Nadia run into Richie. A giant robot (piloted by the alien) then appears and attacks the trio. The alien captures Foster and tortures her for the detonator's location. A mortally wounded Richie informs Steve that he prepared a jury-rigged ejection seat that can be used for escape. Nadia and Steve rescue Foster, and Nadia sacrifices herself by shooting a flaregun at nearby gas tanks to kill the alien; however, it is only damaged by the explosion and pursues the survivors. Foster and Steve use Richie's ejection seat, escaping the robot form, which triggers pin grenades causing an explosion of the missile bomb and sinks Volkov, causing the sentient electricity to disperse in the seawater. A U.S. naval ship later rescues Foster and Steve.

In the distant future, an overcrowded and troubled Earth relies on research conducted by scientists in remote stations across the Solar System. Contact is maintained by spaceships shuttling between the stations and large orbiting space stations. Captain James is preparing to depart from one of these stations around Saturn when he is murdered by Captain Benson. Benson, who was rated "potentially unstable" on a mental exam, then departs from the station using his cargo ship for a small, remote experimental hydroponics research station called Saturn 3. Arriving there, he finds the station run solely by Adam and his younger colleague and lover, Alex. Adam, Alex, and their dog, Sally, enjoy their isolation away from Earth. Alex has spent her entire life in space and knows Earth only from what Adam has told her. It falls to Benson to more fully educate Alex as to the habits and mores of humans who live on Earth, which include drug use. Alex and Adam's idyll is broken when Benson reveals his mission is to replace at least one of the moon's scientists with a robot. The robot—named Hector—is among the first of its kind, a "Demigod Series" model that relies on "pure brain tissue" extracted from human fetuses and is programmed via a direct link to Benson's brain. Adam tells Alex that he is the likely candidate for removal, being that he is close to "abort time" and will have to leave anyway. With Hector assembled, Benson begins preparing the robot, using the neural link implanted in his spine. Thus connected to Benson, Hector quickly learns of Benson's failure of the psychological stability test, and also of his murder of James. With little barrier between the robot's brain and Benson's, Hector is soon imbued with Benson's homicidal nature and his lust for Alex. The robot rebels. Adam and Benson disable the robot while it is recharging and remove its brain. Believing the danger is over, Adam accuses Benson of gross incompetence and orders him to dismantle the robot and return to Earth when the eclipse ends (the eclipse also prevents communication with other stations). Unknown to Benson, Adam, and Alex, Hector remains functional enough to take control of the base's older robots and use them to reassemble his body and reconnect his brain. Unaware of Hector's resurgence, Benson attempts to leave the station while dragging Alex with him. Resuscitated, Hector murders Benson before he can leave with Alex. Hector destroys Benson's spacecraft before the scientists can escape in it, trapping them all on Saturn 3, and assumes control of the station's computer. Trapped in the control room, both Alex and Adam are surprised to see Benson's face on their monitor. The two are directed by a voice they recognise as Benson's to leave the control room, both surprised that Benson is even alive. To their shock, the two are confronted by Hector, now wearing Benson's severed head. A short time later, Alex and Adam wake in their own rooms. To her horror, Alex finds that Hector has installed a brain link at the top of Adam's spine, much like the one that Benson had, and one which will give Hector direct access to Adam's brain. Hector explains that he can 'read' but taking control of Adam 'comes later'. This causes Adam to rebel, and he destroys Hector by tackling him into a waste pit and sacrificing himself with a grenade. In the final scene, Alex is shown aboard a passenger ship returning to Earth. She declines an offer of narcotics from a stewardess and instead looks out of a window for her first glimpse of Earth.

Teenage boy Zack lives on a farm in Tellico Plains, Tennessee with his mother Frances, younger sister Alice, stern and pious old stepfather Nathan Crane and unpleasant, dim-witted stepbrother Cyrus. One night Frances sneaks out of the house while Nathan is asleep and has sex with Mike, a farm-hand who lives in a nearby shack. Suddenly a large meteorite crashes onto the property, emitting an eerie glow. The next morning, Alan Forbes, a physician who lives nearby, visits the crash site and examines the meteorite, which is a large sphere with a hard shell from which a noxious liquid oozes out. Before long, the object dissolves into glowing gelatinous liquid that seeps into the soil. Forbes wants to contact the authorities but is dissuaded by Charlie Davidson, a local realtor and head of the chamber of commerce, who worries that the event will discourage the Tennessee Valley Authority (TVA) from building a new reservoir in the area. Forbes' bored wife Esther also manipulates her husband into keeping quiet, worried their house will lose its value. The mysterious liquid soon begins to affect the farm. The water from the well grows cloudy and tastes unpleasant, fruit and vegetables grow invitingly large but are rotten and inedible inside, and the livestock begin to behave violently and show severe signs of infection. Alice is attacked and injured by infected chickens and Cyrus is nearly killed by a horse. Frances begins to have large boils growing on her face that grotesquely alter her features. She becomes mentally unstable, physically harming herself and attacking her own family. Believing the blight affecting his farm to be a punishment from God for his wife's infidelity, Nathan locks her in their bedroom, not allowing Zack to tell the doctor. Zack keeps himself and Alice free from the infection by consuming clean water and food he steals from Forbes' house. Forbes secretly obtains a sample from the Cranes' well and has it analyzed at a nearby lab. The water is found to contain a strange, unknown element that alters its metabolic properties and molecular structure. Carl Willis, a TVA representative who is surveying the local area for the planned reservoir, enters the Cranes' house looking for a glass of water. Helping himself from the kitchen faucet, he has just started drinking when he is attacked and nearly killed by Frances, who has gone insane and is horribly mutating. Worried that Forbes is going to alert the authorities, Davidson and Esther arrive at the Crane farm looking for the doctor but are attacked by infected dogs who have turned feral. Esther is mauled to death and Davidson hides himself in the cellar only to be killed and seemingly devoured by Frances, who had been locked in there by Nathan. As Nathan and Cyrus examine infected cows in the shed, the cows begin to decay, revealing maggots and worms inside. The cows explode, covering Nathan and Cyrus in insects. By now Nathan and Cyrus are also infected and beginning to go insane. A guilt-ridden Forbes enters the house, hoping to rescue Zack and Alice, but he is surprised and murdered by Nathan, who then barricades the door. Cyrus attacks Alice but Zack fights him off, hiding his sister in a closet. Nathan corners Zack and is about to kill his stepson when he is stabbed by Willis, who has just arrived. The ground begins to glow and heave beneath the house, which starts to fall apart. Zack locates his mother just in time to see her mutated corpse liquefy. As Zack prepares to leave, Cyrus attacks him, but Zack knocks him off the balcony, seemingly killing him. Nathan is knocked out by a support beam as he attempts to stop Zack. Willis gets Zack and Alice out of the house before it collapses, and a dying Nathan and Cyrus are both killed by falling debris. Willis drives away from the farm, taking Zack and Alice with him. Some months later, a heavily bandaged Willis lies in a hospital bed, having become infected more slowly because he only drank a small amount of the farm's water. He is watching a news report on how the authorities are promising that the blight from the farm will be eradicated. Later, at a location in the nearby countryside, the ground and trees begin to heave and break apart at night, revealing more of the glowing alien liquid spreading onto the surface. A large amount of the substance appears, suggesting that the hostile mutagenic entity is still alive, by planning to complete its invasion of Earth.