In 1983, a highly realistic adult amusement park called Delos features three themed "worlds" — Western World (the American Old West), Medieval World (medieval Europe) and Roman World (the ancient city of Pompeii). The resort's worlds are populated with lifelike androids that are practically indistinguishable from human beings, each programmed in character for their historical environment. For $1,000 per day, guests may indulge in any adventure with the android population of the park, including sexual encounters and simulated fights to the death. Peter Martin, a first-time Delos visitor and his friend John Blane, on a repeat visit, go to Westworld. One of the attractions is the Gunslinger, an android whose programming allows guests to participate in gunfights using firearms that prevent them from shooting organic beings. After a night spent with two android prostitutes, John is accosted by the gunslinger Peter killed in the saloon the previous day and Peter once again shoots the android gunslinger dead. Peter is jailed for killing the gunslinger until John breaks him out. During their escape from town, a robotic rattlesnake bites John. The technicians running Delos notice the androids in Roman World and Medieval World experiencing various breakdowns and systemic failures, which may have also spread to Westworld. A serving wench android refuses a guest's advances in Medieval World and the failures escalate until Medieval World's Black Knight android kills a guest in a sword fight. The resort's supervisors try to regain control, but shutting down power to the park traps them in central control. The androids in all three worlds run amok, killing guests while operating on reserve power. Peter and John, recovering from a drunken bar-room brawl, wake up in Westworld's brothel, unaware of the park's breakdown. When the Gunslinger challenges them to a showdown in the street, John treats the confrontation as an amusement, but the android shoots him dead. Peter runs for his life through other areas of the park, pursued by the android. He encounters dead guests, damaged androids and a panicked technician attempting to escape Delos, who is killed by the Gunslinger. Peter descends into the underground control complex, finding the computer technicians asphyxiated. The Gunslinger stalks him into an underground android-repair laboratory. Peter pretends to be an android awaiting repairs, throws acid into the Gunslinger's face, and escapes to the surface inside the Medieval World castle. With damaged optical inputs, the Gunslinger tracks Peter using infrared scanners. Peter discovers burning torches mask his presence, and he sets the Gunslinger on fire and leaves it to burn. Peter encounters a chained woman in a dungeon, but giving her water causes her to short-circuit, revealing her to be an android. The burned shell of the Gunslinger attacks him once again before succumbing to its damage. Peter collapses on the dungeon steps, exhausted and shocked, as the memory of Delos' marketing slogan resonates: "Boy, have we got a vacation for you!"

Rhoda Williams, a brilliant 17-year-old girl who has spent her young life fascinated by astronomy, is delighted to learn that she has been accepted into MIT. She celebrates, drinking with friends, and in a reckless moment, drives home intoxicated. Listening to a story on the radio about a recently discovered Earth -like planet, she gazes out her car window at the stars and inadvertently hits a stopped car at an intersection, putting John Burroughs in a coma and killing his pregnant wife and young son. After serving her four-year prison sentence, Rhoda becomes a janitor at her former high school and struggles with guilt and regret. Hearing more news stories about Earth 2, Rhoda enters an essay contest sponsored by a millionaire entrepreneur who is offering a civilian space flight to Earth 2. One day Rhoda sees John laying a toy at the accident site. She visits his house, intending to apologize. He answers the door and she loses her nerve. Instead, she pretends to be a maid offering a free day of cleaning as a marketing tool for a cleaning service. John, who has dropped out of his Yale music faculty position, has been letting his home and himself go, and accepts Rhoda's offer. He has no idea who she is, and when she finishes asks her to come back the next week. In time, a caring relationship develops and they have sex. Rhoda wins the essay contest and is chosen to be one of the first to travel to Earth 2. John asks her not to go, believing they might have a future together. She finally decides to tell him the truth about who she is. He is upset and throws her out of the house. Rhoda hears an astrophysicist talking on television, describing a "broken mirror" hypothesis which states that upon the sighting of Earth 2 the synchronicity of events happening in both the Earths was broken. Rhoda rushes back to John's house, but he refuses to let her in. She breaks into his house, and he begins to strangle her. He stops, and when she recovers she tells him about the theory and that there might be a possibility for his family to still be alive on Earth 2 and leaves him the ticket. In time, she learns that John accepted the gift and becomes one of the first civilian space travelers to Earth 2. Four months later, on a foggy day, Rhoda approaches her house, discovering her other self from Earth 2 standing in front of her.

Charly Gordon is an intellectually disabled man who lives in Boston. He has a desire to learn and has attended night school for two years, taking a class taught by Alice Kinnian. He learns to read and write, though his spelling and penmanship are poor and he is unable to spell his own name. He works as a janitor at a bakery, where his coworkers amuse themselves by taking advantage of his disability, and he enjoys playing with children at a playground. Alice takes Charly to researchers Dr. Richard Nemur and Dr. Anna Straus, who have been investigating methods for increasing intelligence. Having successfully tested a surgical procedure on a lab mouse named Algernon, they are looking for a human test subject. They put Charly through a battery of aptitude tests and have him try to solve a series of paper mazes while Algernon runs through models of them. Charly consistently loses to Algernon, but is selected for the surgery. After surgery, Charly loses to Algernon again and is frustrated at not immediately becoming smarter. After some time passes, he finally beats Algernon and his intelligence begins to increase. His coworkers tell him to operate a complex machine, hoping that he will break it so they can have the day off, but he successfully operates it. Embarrassed and frightened by his new intelligence, they persuade the bakery owners to fire Charly. Alice continues teaching him, but his intelligence continues to increase and eventually surpasses hers. Lacking emotional maturity, Charly becomes infatuated with Alice and confesses his love for her, but she sharply rejects his advances. He flees in an act of rebellion but eventually returns to Boston, and the two start to consider marriage. Nemur and Straus present their research at a scientific convention. After playing the film of Charly's original aptitude tests, they bring him out for a question-and-answer session. He is now the intellectual equal or superior of everyone in the audience, but he has also developed a cynical view of humanity that the attendees mistake for humor. He reveals that Algernon has lost his enhanced intelligence and died, facts that the research team kept from him, and expects to undergo a similar decline. Fleeing the convention and seeing hallucinations of his previous self everywhere, Charly stops to help a busboy pick up a tray of dropped glasses after observing that he is intellectually disabled. Charly overhears Alice, Nemur, and Straus discussing his situation and offers to assist in finding a way to preserve his intelligence, but their combined efforts prove fruitless. He falls into a depression and asks Alice never to visit him again. Some time later, Alice sees Charly playing with children on the playground, having fully regressed to his original level of disability.

George Newman, a daydreaming slacker who bounces between jobs, is put in charge of Channel 62, a UHF television station, after his uncle Harvey Bilchik wins ownership of it in a poker game. George and his friend Bob Steckler realize the station is nearly bankrupt, subsisting on reruns of old shows like The Beverly Hillbillies and Mister Ed. When a package meant for its competitor, VHF station Channel 8, is misdelivered to Channel 62, George decides to deliver it himself, only to be rudely dismissed by RJ Fletcher, owner and CEO of Channel 8. Outside, George meets a janitor, Stanley Spadowski (whom RJ had recently and unfairly fired after falsely accusing him of discarding a missing report), and hires him at Channel 62. Bob and George create new programs, including the live children's show Uncle Nutzy's Clubhouse (hosted by George), but all of them unfortunately fail to increase viewership. While fretting over their finances, George neglects his girlfriend Teri's birthday dinner and she breaks up with him. The next day, during the Uncle Nutzy broadcast, a depressed George abandons the set, hands over hosting responsibilities to Stanley, and visits a bar with Bob to drown their sorrows, but discovers the patrons enjoying Stanley's slapstick antics on Channel 62. Inspired, the pair create various bizarre shows to fill the schedule, headlined by the re-titled Stanley Spadowski's Clubhouse. Infuriated that Channel 62's ratings now rival those of Channel 8, including a majority of Top Five shows, RJ discovers Harvey owes his bookie Big Louie $75,000 by the end of the week, and offers to pay the debt in exchange for the deed to Channel 62. George launches a telethon to sell stock in the station, which would not only save it from RJ but also make it publicly owned. RJ's henchmen stall the telethon by kidnapping Stanley, whom George and several staff-members eventually rescue. RJ again attempts to stall the telethon with a televised public statement, but Channel 62 engineer Philo hijacks it with secretly recorded footage of RJ insulting the town's population to Teri's face during her visit to his Channel 8 headquarters. The telethon ends about $2,000 short of its goal. Harvey concedes victory to RJ who, instead of immediately taking ownership, gloats to the crowd. Meanwhile, a homeless man approaches George, asking to buy the remaining stock with money obtained by selling a rare 1955 doubled die cent that RJ, unaware of its true value, gave him when he was begging for change. George pays off Big Louie, Harvey signs the ownership transfer, and the station officially becomes publicly owned. Due to both its tardiness in filing its broadcast license renewal and the tirade that Philo broadcast, Channel 8 has its license revoked by the FCC, which subsequently shuts it down. After the Channel 62 staff and audience celebrate, George and Teri reconcile.

Ray, recently fired from his job as a theme park guide, spends the evening with his friends Pete and Toby at the cinema and later at a pub. There, they write a satirical "Letter to Hollywood" criticising bad films, using a page from Toby’s notebook. Ray encounters a woman named Cassie, who claims to be a time traveller working to fix "time leaks." She warns him about "Editors," operatives from the future who eliminate artists at their peak to preserve cultural standards. Ray believes the encounter is a prank arranged by his friends; they deny it and think he is making up meeting Cassie. Soon after, Pete experiences a bizarre vision of a massacre at the pub, including a bearded version of himself. The group discovers a time leak in the men's toilet, which allows them to travel 30 minutes into the past and encounter earlier versions of themselves. Cassie returns, stating she has repaired the leak, but anomalies continue to occur. They enter a post-apocalyptic version of the pub, and Pete briefly disappears into the time leak, returning dishevelled and traumatized. The group attempts to avoid paradoxes caused by interacting with their past selves. During a party at the pub that is themed around their future selves, they meet Millie, another time traveller who claims to be Cassie's mentor but is later revealed to be an Editor sent to kill them at the moment of their greatest potential. Believing the "Letter to Hollywood" may be responsible for their future fame, Ray, Pete, and Toby consider destroying it to prevent Millie’s interference. Millie incapacitates Cassie and offers to make them legends in exchange for the paper, but they refuse. A confrontation ensues, and Millie appears to kill everyone in the pub. An earlier version of Pete enters, witnesses the aftermath, and flees. A severely injured Ray spills beer on the paper, rendering it illegible. This act triggers a reset of the timeline, returning the trio to their original state at the pub, with full memories of the events, but with the paper destroyed. As they leave, believing the situation resolved, Cassie reappears through a portal, now claiming she and Ray have been in a relationship in an alternate timeline. She warns of widespread time leaks and urges them to help save the world within fourteen hours. The group agrees to follow her into a parallel universe. In mid- and post-credits scenes, multiple versions of Pete and Toby appear, suggesting ongoing complications from the time travel events.

The CIA has covertly hired Professor Jerry Hathaway at Pacific Tech University to develop the power source for "Crossbow", a laser weapon precise enough to commit illegal political assassinations from outer space. Hathaway uses his position to recruit brilliant students to do the work for him, diverting the CIA's funding into building his new house. Hathaway recruits high school student Mitch Taylor, a budding genius in laser physics. Mitch is roomed with Chris Knight, a legend in the "National Physics Club" and one of Mitch's idols. Mitch's ideal of Chris is shattered, however, when Chris turns out to be more of a slacker than a hard-working student. Meanwhile, Hathaway hopes Mitch will encourage Chris to straighten up his act and that their two exceptional minds can develop a proper power source for Crossbow. Mitch also befriends Jordan Cochran, a hyperactive insomniac student for whom he gradually develops romantic feelings. Kent, Hathaway's graduate student (and toady), reports Mitch for attending a pool party with Chris instead of working on the laser. Hathaway lambasts Mitch, who breaks down and tearfully calls his parents. Kent secretly records the call and uses the recording to humiliate Mitch. As Mitch begins packing to leave, Chris explains the pressures of school and burdens of being highly intelligent by relating the history of genius and former Pacific Tech student Lazlo Hollyfeld. Hollyfeld suffered a nervous breakdown when he discovered his creations were being used to kill, and he now lives hidden in the university's tunnels, accessed from beneath Chris and Mitch's closet. Chris, fearing the same could happen to him, learned to lighten up and enjoy life. Mitch agrees to stay, and they exact revenge on Kent by disassembling his car, a 1972 Citroën DS, and reassembling it in his dorm room. Hathaway, angry about the still-incomplete project and Chris's attitude, informs Chris that he intends to prevent him from earning a degree, blackball him, and give a coveted job, originally promised to Chris, to Kent instead. Chris is disheartened and Mitch must use Chris's same argument to convince him to stay. The two create a new laser, but Kent sabotages it, causing it to explode. Though initially despondent, the incident inspires Chris to design and build a six-megawatt excimer laser, which burns a hole through the campus when it is test-fired. Hathaway reverses his position, giving Chris a degree and the job. As Chris and Mitch celebrate, Hollyfeld arrives and informs them that, with certain modifications, their laser could be used as a weapon. A panicked Chris returns to the lab to find the laser gone, as well as Kent's projects: a mirror and a tracking system which together can weaponize Chris's laser. Jordan and fellow project member "Ick" Ikagami surreptitiously implant a radio transmitter in Kent's braces, which Mitch uses to convince him he is speaking to Jesus. Kent divulges the date of the test, and the group tails Hathaway to learn the location of the Air Force base the CIA is using. Chris and Mitch sneak onto the B-1 Lancer bomber where their equipment has been installed and assist Hollyfeld in reprogramming the laser. Outside Hathaway's home, Chris, Mitch, Jordan, and Ick meet Dean Meredith and a Congressman, to whom they had reported Hathaway's plan. Kent arrives and goes inside the house. The laser test begins and, instead of firing on the target, fires on Hathaway's house, activating a gigantic popcorn popper. Kent is launched out the front door on a popcorn wave. Hollyfeld arrives in an RV—which he has won in a sweepstakes by submitting over a million entries—to tell them he is leaving. Hathaway, who hates popcorn, arrives afterwards to find his house destroyed by popcorn.

In 1967, Edward Jessup is a Columbia University psychopathologist studying schizophrenia. He thinks that "our other states of consciousness are as real as our waking states." He begins experimenting with sensory deprivation using a flotation tank, aided by like-minded researchers, Arthur Rosenberg and Mason Parrish. At a faculty party, he meets fellow "whiz kid" and his future wife, Emily. Over a decade later, Edward is a tenured professor at Harvard Medical School. He and Emily have two daughters and are on the brink of divorce when they reunite – for the first time in seven years – with the couple who had first introduced them. When Edward hears about the Hinchi tribe, whose members experience shared hallucinatory states, he decides to travel to Mexico in order to participate in their ceremony. During the climb up into the Hinchi hill country (a plateau covered in spectacular mushroom-shaped ventifacts), Edward is told by his guide, Eduardo Echeverria, that the Hinchi use in their ceremonies a potion containing the sacred mushroom Amanita muscaria and the shrub sinicuiche, which they are collecting for next year's ceremonies. The tribe calls sinicuiche by a Hinchi name meaning "first/primordial flower" in recognition of the deep memory states which it can evoke. An indigenous elder ("the brujo ") is seen with a root in his hand, which he asks Edward to hold, before cutting Edward's hand in order to add drops of blood to the mixture he is preparing. Immediately after consuming the mixture, Edward experiences bizarre, intense hallucinations, including one of the petrifaction and subsequent erosion by blown sand of Emily and himself. The following morning, Edward leaves the Hinchi plateau under a cloud, having killed, while in his intoxicated state, a large specimen of the Hinchi's sacred monitor lizard. He returns to the U.S. with a sample of the Hinchi potion for analysis by his colleagues and further self-experimentation and continues taking it in order to take his exploration of altered states of consciousness to a higher level. When toxic concentrations of the substance make increased dosage dangerous, Edward returns to sensory deprivation, believing it will enhance the effects of the substance at his current dose. Repairing a disused tank, he uses it to experience a series of increasingly drastic visions, including one of early Hominidae. Monitored by his colleagues, Edward insists that his visions have "externalized". Emerging from the tank, his mouth bloody, frantically writing notes because he is unable to speak, he insists on being X-rayed before he "reconstitutes." A radiologist inspecting the X-rays says they belong to a gorilla. In later experiments, Edward experiences actual, physical biological devolution. At one stage, he emerges from the isolation tank as a feral and curiously small-statured, light-skinned caveman, going on a rampage in town and breaking into a zoo before returning to his natural form. In the final experiment, he experiences a more profound regression, transforming into an amorphous mass of conscious, primordial matter. An energy wave released from the experiment stuns Edward's colleagues and destroys his tank. Emily recovers and finds a swirling maelstrom where the tank had been. She searches in the vortex for Edward, finding him as he is on the brink of becoming a non-corporeal energy being that will vanish from reality if this transformation reaches its conclusion. His friends bring Edward home, hoping that the transformations will end. Watched over by Emily, Edward begins to regress uncontrollably, the transformations no longer requiring the intake of "first flower" or sensory deprivation. Urging Edward to fight the change, Emily grabs his hand, being enveloped by the primordial energy emanating from him. The sight of Emily apparently being consumed by the energy stirs the human consciousness in Edward's devolving form. He fights the transformation off by banging repeatedly into the hallway wall and returns to his human form. Edward then grabs Emily's form, and she returns to normal. The movie ends with the two on the floor in a nude embrace as Edward tells Emily that he loves her, which she had longed to hear him say.

Jess prepares to take her autistic son Tommy on a boat trip with her friend Greg. When Tommy becomes upset, she tells him that he just had a bad dream. Jess goes to a Florida harbor without Tommy, explaining that he is at school, and boards Greg's boat with his deckhand Victor, his married friends Sally and Downey, and Sally's friend Heather. On the boat she has a dream about crabs on a beach, and wakes up disturbed, but then she forgets what disturbed her. At sea, a storm approaches, and while Greg radios the Coast Guard, he listens to a distress signal from a woman pleading for help. She says that someone is killing everyone but is cut off before she can provide her location. The sudden storm capsizes the boat. Heather is swept away, but the others climb onto the overturned sailboat when the storm clears. The five survivors board a passing ocean liner, the Aeolus. It appears to be deserted even though they saw the silhouette of a person aboard. Jess experiences a sense of déjà vu as they explore the ship. They find Jess's keys and fresh food in the dining room. Jess spots someone watching them and Victor gives chase. Jess and Greg find the words "go to theater" written in blood on a mirror, but Greg insists the crew must be playing a prank. Jess returns to the dining room, where the food is now rotting. Victor, with a head wound, tries to strangle Jess, but she fights him, and he collapses. Jess hears gunfire and follows it to the ship's theater, where Greg lies dead from a gunshot. Sally and Downey say that Greg told them Jess shot him. Someone in a burlap mask shoots Sally and Downey. Jess runs, grabs an ax and disarms the shooter, who tells her, "You have to kill them; it's the only way to get home" before Jess knocks her overboard. Jess hears yelling and sees another copy of her group on Greg's boat, who spot her (as the earlier unidentified figure). This new set of passengers boards the ship. They spot her after she drops her keys, and she attempts to warn the new Victor when he chases her, only to accidentally injure his head on a wall hook. She finds dozens of her own lockets and notes in her own handwriting telling her to kill them all. She takes a shotgun and confronts the new group, intending to "change the pattern", but a third Jess shoots the new Greg and stabs the new Downey and Sally. The old Jess chases the new Sally, who sends the distress signal heard on Greg's boat. Jess catches up to her on a deck filled with dozens of Sally's corpses, and Sally succumbs to her wound as, below them, the new Jess kills the third Jess. The overturned boat returns again with another copy of her group, and the old Jess realizes the loop restarts once everyone is killed. Desperate to stop the loop, she sets the loop into motion by writing on the mirror in blood, dumping bodies overboard, and telling the latest Sally and Downey to go to the theater. She then arms herself, dresses in the shooter's outfit, and puts on a burlap mask. After she shoots the latest group and is disarmed, she urges the latest Jess to kill everyone, before being knocked overboard. She awakens near crabs on a beach, having washed ashore, and she discovers that it is earlier that morning. She returns home and watches from outside her house as her earlier self yells abusively and strikes Tommy out of frustration with his autism. She distracts her counterpart with the doorbell, then kills her, and tells Tommy that he just had a bad dream. She puts the bagged body in her car's trunk and leaves with Tommy, vowing to him that things will change. A seagull hits their windshield and dies, but after she tosses it off the road, she sees there's a pile of many dead seagulls. Realizing she is still trapped in the loop, Jess hurriedly drives away, but crashes into a truck, killing Tommy. A taxi driver approaches her. Jess asks him to take her to the harbour, evidently hoping to bring back her son. The driver tells her he will wait for her, and she promises him that she will return. Exhausted, she joins the others on Greg's boat, starting the loop again.

In Russia, the media covers Tony Stark 's disclosure of his identity as Iron Man. Ivan Vanko, mourning the death of his father Anton Vanko —a former Stark Industries employee, sees this and builds the same miniature arc reactor as Stark's using old Stark Industries blueprints left behind by Anton. Six months later, Tony wants to continue the legacy of his father Howard, and re-institutes the Stark Expo in New York City's Flushing Meadows–Corona Park. He also resists pressure to turn over his armored suits to the government and Stark's rival, Justin Hammer. However, Stark learns that the palladium core in the arc reactor that keeps him alive and powers the armor is slowly poisoning him, and he is unable to find a substitute. Growing increasingly despondent about his impending death, and refusing to tell anyone about his condition, Stark appoints his assistant Pepper Potts as CEO of Stark Industries and promotes Stark employee "Natalie Rushman" to replace her as his assistant. Stark competes in the Monaco Historic Grand Prix, where he is attacked in the middle of the race by Vanko, who wields electrified whips powered by his arc reactor. Stark dons his armor and defeats Vanko, but the armor is severely damaged. Vanko explains that he intended to prove to the world that Iron Man is not invincible. Impressed by Vanko's performance, Hammer fakes Vanko's death while breaking him out of prison and asks him to build a line of armored suits to upstage Stark. Vanko decides that unmanned drones are better to eliminate the human factor. During his birthday party, Stark gets drunk while wearing the Iron Man suit. Annoyed by Tony's recklessness, Stark's best friend, U.S. Air Force Lieutenant Colonel James Rhodes, dons Stark's prototype armor and tries to restrain him. The fight ends in a stalemate, and Rhodes confiscates the prototype armor for the U.S. Air Force. Nick Fury, director of S.H.I.E.L.D., approaches Stark. Fury reveals that "Rushman" is S.H.I.E.L.D. agent Natasha Romanoff and that Fury personally knew Howard Stark, who was a founder of S.H.I.E.L.D. Fury explains that Vanko's father and Howard invented the arc reactor together, but Howard had Anton deported when the latter tried to sell it. The Soviets then sent Anton to the Gulag. Fury gives Stark some of his father's old material. In a diorama of the 1974 Stark Expo, Stark finds a diagram of the atomic structure of a new element. With the aid of his A.I., J.A.R.V.I.S., Stark determines it can replace his arc reactor's current palladium core, and successfully synthesizes it. When Stark learns that Vanko is still alive, he goes to Hammer's exhibition at the expo. The armored drones are unveiled, with Rhodes – in a heavily weaponized version of the prototype armor, dubbed "War Machine" – as their leader. Just as Stark arrives to warn Rhodes, Vanko takes remote control of all the drones and Rhodes's armor and attacks Stark. Hammer is arrested for breaking Vanko out of prison while Romanoff and Stark's bodyguard Happy Hogan infiltrate Hammer's factory. Vanko escapes, but Romanoff gains access to Hammer Industries software and returns control of Rhodes's armor to him. Together, Stark and Rhodes defeat Vanko, who dies by suicide via blowing up his suit and the drones. At a debriefing, Fury informs Stark that because of his difficult personality, S.H.I.E.L.D. intends to use him only as a consultant moving forward. Stark and Rhodes receive medals for their heroism. In a post-credits scene, S.H.I.E.L.D. agent Phil Coulson discovers a large hammer in New Mexico.

Black mine inspector Ralph Burton becomes trapped in a cave-in at a Pennsylvania coal mine. He can hear rescuers digging towards him, but after five days they slow down and then stop completely, along with the drainage pumps keeping the shaft from flooding. Ralph frantically digs his own way out, but upon emerging from the mine, he finds a world devoid of any people, living or dead. Discarded newspapers provide an explanation: one proclaims "UN Retaliates For Use Of Atomic Poison", another that "Millions Flee From Cities! End Of The World". Ralph later plays tapes at a radio station and learns that an unknown country had dispersed large quantities of radioactive sodium isotopes into the atmosphere. The resulting lethal dust cloud spread around the world, killing every human who came into contact with it over a five-day period before the isotopes decayed into a harmless state. Ralph travels to New York City in search of survivors, but in vain. He restores power to a building where he takes up residence. To stave off loneliness, he takes in a pair of mannequins. As the solitude starts to become intolerable, he throws a mannequin off the building, and hears a scream. Sarah Crandall, a White woman in her early twenties, had been living in the city and surreptitiously observing Ralph for some time, but was afraid to reveal herself. She screamed because she thought Ralph had committed suicide. Ralph, an engineer, gets utilities working again and raises their standard of living, but the two remain in separate apartment buildings. Even as they become friends and grow closer, vestiges of racial division become evident when Sarah casually uses the phrase that she is " free, white, and 21 " to describe her ability to make decisions. Ralph describes the phrase as "an arrow in my guts." In the same conversation, Sarah laments that "there is nobody left to marry." Resentful, Ralph refuses Sarah's suggestion that she move into his apartment building. Ralph maintains his distance when it becomes clear that Sarah is developing stronger feelings for him, unsure how she will react if they discover others alive. Despite living in a post-apocalyptic world, tensions remain that were instilled by the mores earned in a racially segregated American society. Ralph regularly broadcasts on the radio in the hope of contacting other survivors, and eventually receives a transmission in French, confirming there are others. One day, ill white man Benson Thacker arrives by boat. Ralph and Sarah nurse him back to health, but once he recovers, Ben sets his sights on Sarah and sees Ralph as a rival. Ralph is torn by conflicting emotions. He avoids Sarah as much as possible to give Ben every opportunity to win her affections, but cannot quite bring himself to leave the city. Ben finally grows tired of the whole situation, realizing he stands little chance with Sarah as long as Ralph remains nearby. He warns Ralph that the next time he sees him, he will try to kill him. The two armed men hunt each other through the empty streets. Finally, Ralph passes by the United Nations headquarters, climbs the steps in Ralph Bunche Park, and reads the inscription "They shall beat their swords into plowshares. And their spears into pruning hooks. Nation shall not lift up sword against nation. Neither shall they learn war any more", from the Book of Isaiah. He throws down his rifle and goes unarmed to confront Ben, who in turn finds himself unable to shoot his foe. Defeated, he starts walking away. Sarah appears. When Ralph starts to turn away from her, she makes him take her hand; then she calls to Ben and gives him her other hand. Together, the three walk down the street to build a new future together. The film ends not with "The End" but with "The Beginning."