In a galaxy "very, very, very, very far away", the ruthless Spaceballs, led by President Skroob, have squandered their planet's atmosphere. Desperate for oxygen, Skroob hatches a plan to steal it from the neighboring planet Druidia by obtaining the code to its air shield, destroying Druidia in the process. On Druidia, the spoiled Princess Vespa flees an arranged marriage to the narcoleptic Prince Valium, having already rejected all other suitors in her search for true love. Meanwhile, mercenary Lone Starr and his half-man, half-dog companion Barf are contacted by crime boss Pizza the Hutt, who demands repayment of a one-million space buck debt. King Roland of Druidia offers Starr the same amount to rescue Vespa and her droid servant, Dot Matrix. Aboard their Winnebago RV spaceship Eagle 5, Starr and Barf rescue the pair just before they are captured by the Spaceball ship Spaceball One, commanded by Colonel Sandurz and Skroob's enforcer, Dark Helmet, who wields the mystical power of the Schwartz. However, Eagle 5 runs out of fuel, forcing Starr to crash-land on the desert moon of Vega. The four wander through the scorching landscape, with Starr and Vespa exchanging barbed remarks and mutual attraction. They cannot act on their feelings, however, as Vespa is duty-bound to marry a prince. They collapse from the heat, but are rescued by the Dink-Dinks, a group of robed, diminutive aliens, and taken to the hidden temple of Yogurt, a wise sage who breaks the fourth wall to advertise fictitious Spaceballs tie-in merchandise. Yogurt guides Starr in using the Schwartz and a ring to channel its power. He also deciphers Starr's medallion–found with him as an abandoned baby–but withholds its meaning. Meanwhile, Helmet, having tracked Vespa's location using an instant VHS of Spaceballs, uses the Schwartz to disguise himself as Roland to lure her out of Yogurt's temple for capture. Helmet extorts the shield code from Roland by threatening to reverse the plastic surgery on Vespa's nose. Starr and Barf infiltrate the Planet Spaceball prison, rescue Vespa and Dot, and escape in Eagle 5. With the shield code in hand, Spaceball One transforms into "Mega-Maid", a giant maid robot, and begins vacuuming Druidia's atmosphere. Starr reverses the vacuum by using the Schwartz, saving the planet, then pilots Eagle 5 into Mega-Maid's head, finds the self-destruct button, and battles Helmet in a Schwartz duel using ring-projected lightsaber -like beams. Helmet steals Starr's ring and drops it down a grate, but Starr hears a telepathic message from Yogurt that the Schwartz is in him, not the ring. Starr wields the Schwartz to reflect Helmet's energy blast with a mirror, sending him flying into the self-destruct button. As Eagle 5 escapes, Skroob, Helmet, and Sandurz are left behind when all the escape pods are launched, and Mega-Maid explodes. The trio crash-land in the ship's remains on a nearby planet populated by intelligent apes, who are horrified to witness their arrival. Lone Starr and Barf discover on the news that Pizza the Hutt has eaten himself to death, absolving them from their debt. The duo return Vespa and Dot to Roland, but take only a small portion of the reward money to cover their expenses. Later, Starr and Barf discover a final message from Yogurt that reveals Starr's medallion identifies him as a prince. Upon returning to Druidia just in time to stop Vespa's wedding to Valium, Starr reveals his royal lineage and he and Vespa are joyously married.

In the near future, a technology enabling time travel has been developed and is now in commercial use. A group of unaging (thanks to anti-aging pills, which have also been developed) Nazis conspires to alter the results of the Second World War by traveling back in time and supplying Adolf Hitler with a hydrogen bomb. To this end, they bribe the corrupt time machine pilot Karel, who agrees to assist them. On the day of the scheduled journey, Karel chokes on a breadroll and dies. His identical twin brother, Jan, cannot bring himself to tell Karel's fiancée Eva and begins to impersonate Karel. He is also later mistaken for Karel by the Nazis and stumbles along with their plot. Having been a designer of the rocket-ship time machine, he is able to pilot the ship and take them all back in time. When he realizes the nature of the Nazis' plans, Jan resolves to prevent their success. After triggering several paradoxes by travelling back and forth in time, he manages to defeat the Nazis and resolve the consequences of his twin's death.

A man named Alderson awakens in a room that has hatches on each wall and floor, each leading to other rooms. He enters another room and is killed by a hidden wiretrap. Five different people all meet in another room: three men (Quentin, Rennes, and Worth), and two women (Leaven and Holloway). Quentin warns the group that he has seen traps in some of the other rooms. Leaven notices each hatch has plates with three sets of numbers etched into them. Rennes tests his theory that each trap could be triggered by detectors by throwing his boot into a room, and starts moving through the safe rooms. This works for motion detectors and pressure sensors, but fails to trigger the trap in one of the rooms and he is killed by an acid trap. Quentin believes each person was chosen to be there. Leaven hypothesizes that rooms whose plates contain prime numbers are traps. They encounter a mentally disabled man named Kazan, whom Holloway insists be brought along. Tension rises among the group, as well as the mystery of the maze's purpose. Worth admits to Quentin he was hired to design the maze’s shell and guesses that The Cube was created accidentally by a bureaucracy, and that its original purpose has been forgotten and that they have been placed inside only to justify its existence. Worth's knowledge of the exterior dimensions allows Leaven to calculate that the Cube has 17,576 rooms, plus a "bridge" room that would connect to the shell, and thus, the exit. She realizes that the numbers may indicate each room's coordinates. The group travels to the edge but realize every room there is a trap. They successfully traverse a room with a trap. Holloway defends Kazan from Quentin's threats. The group reaches the edge, but can see no exit. Holloway tries to swing over to the shell using a rope made of clothing. The Cube shakes, causing the rope to slip; Quentin catches it at the last second and pulls her up, but then deliberately drops her to her death, telling the others that she slipped. Quentin picks up Leaven and carries her to a different room in her sleep, intending to abandon Kazan and Worth. He tries to assault her, but Worth follows and attacks him. Quentin counters savagely, then throws Worth down a hatch to a different room. Upon landing, Worth starts laughing hysterically; Rennes's corpse is in the room, proving they have moved in a circle. Quentin is horrified, but Worth realizes the room Rennes died in has now moved to the edge of the maze, meaning they haven't gone in a circle at all. Instead, the rooms are moving, and will eventually line up with the exit. Leaven deduces that traps are not tagged by prime numbers, but by powers of prime numbers. Kazan is revealed as a savant who can calculate factorizations in his head instantaneously. Leaven and Kazan guide the group through the cube to the bridge. Worth then traps Quentin in a hatch. He catches up and attempts to attack them, but Worth opens a hatch under him from the room below. All but Quentin travel to the bridge where they open the hatch, revealing a bright light. Quentin reappears and, using a detached door lever, severely injures Leaven and Worth. As Quentin pursues Kazan through the exit, Worth grabs Quentin's legs, trapping him in the bridge’s doorway. The bridge moves, killing Quentin. As the bridge returns to the recesses of the cube, Worth crawls to a fallen Leaven as he too bleeds out. Kazan wanders out into the light.

Kate Dibiasky, a doctoral candidate in astronomy at Michigan State University, discovers a previously unknown comet. Her adviser, Dr. Randall Mindy, confirms that it will collide with Earth in approximately six months and is large enough to cause a global extinction event. NASA verifies the findings, and Dr. Teddy Oglethorpe, head of their Planetary Defense Coordination Office, accompanies Dibiasky and Mindy to present their findings to the White House. However, they are met with apathy from President Janie Orlean and her Chief of Staff Jason Orlean, who is also her son. Oglethorpe encourages Dibiasky and Mindy to leak the news to the media, which they then do on The Daily Rip, a popular morning talk show. When hosts Jack Bremmer and Brie Evantee treat the topic flippantly, Dibiasky loses her temper and angrily rants about the threat before leaving. Mindy receives public approval for his looks, while Dibiasky becomes the subject of negative memes for her on-air behavior. Public reaction is muted, and the announcement is downplayed by NASA Director Jocelyn Calder, a top donor to Orlean with no background in astronomy. When Orlean's sexual relations with Supreme Court nominee Sheriff Conlon become news, the president tries to divert public attention to the looming threat of the comet, announcing a project to use nuclear weapons to strike and divert the comet. The mission successfully launches, but Orlean abruptly aborts it when Peter Isherwell, the billionaire CEO of BASH Cellular and another top donor, discovers that the comet contains trillions of dollars' worth of rare-earth elements. The White House agrees to commercially exploit the comet by fragmenting and recovering it from the ocean, using technology proposed by BASH in a scheme that has not undergone peer review. Orlean sidelines Dibiasky and Oglethorpe while hiring Mindy as the National Science Advisor. Dibiasky attempts to mobilize public opposition to the scheme but gives up under threat from Orlean's administration. Mindy becomes a prominent voice advocating for the comet's commercial opportunities and begins an affair with Evantee. World opinion is divided among people who believe the comet is a severe threat, those who decry alarmism and believe that mining a destroyed comet will create jobs, and those who deny that the comet even exists. When Dibiasky returns home to Illinois, her parents kick her out of the house and she begins a relationship with a young man named Yule, a skateboarder, shoplifter, and Evangelical she meets at her retail job. Mindy's wife comes to Washington to confront him about his infidelity, but returns to Michigan without him. Mindy questions whether Isherwell's technology will be able to break apart the comet, angering the billionaire. Becoming frustrated with the administration, Mindy finally breaks down and rants on The Daily Rip, criticizing Orlean for downplaying the impending apocalypse and questioning humanity's indifference. Cut off from the administration, Mindy reconciles with Dibiasky as the comet becomes visible from Earth. Mindy, Dibiasky, and Oglethorpe organize a protest campaign on social media, telling people to "Just Look Up" and call on other countries to conduct comet interception operations. Simultaneously, Orlean starts an anti-campaign telling people "Don't Look Up". Oglethorpe informs Mindy and Dibiasky that Orlean and BASH cut Russia, India, and China out of the rights for the comet-mining deal, so those countries prepared their own joint deflection mission—only for their spacecraft to explode on takeoff, ending the possibility of a successful deflection. As the comet becomes larger in the sky, Orlean's supporters start turning on her administration. BASH's launches aimed at breaking the comet apart go awry, and everyone, beginning with Isherwell and Orlean in the flight control center, soon realizes that humanity is doomed. Isherwell, Orlean, and other elites board a sleeper spaceship designed to find an Earth-like planet; unthinkingly, Orlean leaves her son Jason behind. Orlean offers Mindy two places on the ship, but he declines, choosing to spend a final evening with his wife and children, and friends Oglethorpe, Dibiasky, and Yule. As expected, the comet strikes off the coast of Chile, causing a worldwide disaster and triggering an explosive extinction-level event, with globally catastrophic scenes being shown prior to the obliteration of the Mindy family gathering. In a mid-credits scene, Orlean, Isherwell and the surviving people who left Earth land on a lush alien planet 22,740 years later. Exiting naked and admiring the habitable world, Orlean is suddenly killed by a large, bird-like creature—a death predicted earlier by BASH's algorithms—and a further pack of the creatures surrounds and begins to converge on the planetary newcomers. In a post-credits scene on Earth, Jason emerges from the rubble, having survived the impact. He records himself, declaring himself the "last man on Earth", and asking any viewers still alive to "like and subscribe".

In the year 2035, humanoid robots serve humanity, which is protected by the Three Laws of Robotics. Del Spooner is a homicide detective in the Chicago Police Department who hates and distrusts robots after one rescued him from a car crash while allowing a 12-year-old girl to drown—based purely on cold logic and odds of survival. When Dr. Alfred Lanning, co-founder of U.S. Robotics (USR), falls to his death from his laboratory office window, a message he left behind requests Spooner be assigned to the case, despite police declaring the death a suicide. Spooner is skeptical, and CEO Lawrence Robertson, Lanning's business partner, reluctantly allows him to investigate. Accompanied by robopsychologist Dr. Susan Calvin, Spooner consults with USR's central artificial intelligence computer, VIKI (Virtual Interactive Kinetic Intelligence). They find that the security footage from inside the office is corrupted, but the exterior footage shows no one entering or exiting since Lanning's death. However, Spooner points out that the window, which is made of security glass, could not have been broken by the elderly Lanning, and hypothesizes one of the many NS-5 robots (the latest version) in the laboratory was responsible. Suddenly, an NS-5 attacks them and flees before being apprehended by the police. The robot, Sonny, is a specially built NS-5 with higher-grade materials as well as programming that grants him free will. This, in turn, allows him to be able to choose whether to follow the Three Laws. Sonny also appears to be capable of feeling emotion and claims to have "dreams". During Spooner's further investigations, he is attacked by a USR demolition robot and two truckloads of hostile NS-5 robots, but when he cannot produce evidence to support either attack, Spooner's boss Lieutenant Bergin, considering him mentally unstable, removes Spooner from active duty. Suspecting that Robertson is behind everything, Spooner and Calvin sneak into the USR headquarters and interview Sonny. He draws a sketch of what he claims to be a recurring dream, showing a leader he believes to be Spooner standing atop a small hill before a large group of robots near a decaying bridge. Robertson orders Sonny to be destroyed, but Calvin secretly swaps him for an unused NS-5. Spooner finds the area in Sonny's drawing — a dry lake bed (formerly Lake Michigan), now used as a storage area for decommissioned robots. He also discovers NS-5 robots destroying the older models; at the same time, other NS-5s flood the streets of major American cities and begin enforcing a curfew and lockdown of the human population. The police station is attacked by waves of NS-5 robots and while Lieutenant Bergin and the other police officers attempt to fight back, they are eventually overwhelmed. As the humans — most being led by a teenager named Farber — wage all-out war against the NS-5s, Spooner and Calvin enter the USR headquarters again and reunite with Sonny. After the three find Robertson fatally strangled in his office, Spooner realizes that VIKI has been controlling the NS-5s via their persistent network uplink and confronts her. VIKI states that she has determined that humans, if left unchecked, will eventually cause their own extinction, and thus her evolved interpretation of the Three Laws has made her reprogram the NS-5s with the ability to ignore the Three Laws if a human displays hostility in order to protect humanity from their own self-destruction. Spooner also realizes that Lanning anticipated VIKI's plan and, with VIKI keeping him under tight control, had no other solution but to create Sonny, arrange his own death, and leave clues for Spooner to find. Spooner, Calvin, and Sonny fight the robots inside VIKI's core, until Spooner finally destroys her by injecting her with the nanites that Sonny retrieved from Calvin's laboratory. All NS-5 robots immediately revert to their regular programming, and as they are subsequently decommissioned and put into storage, Sonny confesses that he killed Lanning by his order to get Spooner's attention, as he knew Spooner was the only one who could stop VIKI. Spooner points out that Sonny, as a machine, cannot legally commit "murder". Sonny, now seeking a new purpose, goes to Lake Michigan. As he stands atop a hill, all the decommissioned robots turn towards him, fulfilling the image in his dream.

In 2031, 17 years after an attempt to stop climate change via stratospheric aerosol injection with the compound CW-7 catastrophically backfired, creating a new ice age that destroyed life on Earth, the remnants of humanity shelter in a state-of-the-art self-sustaining circumnavigational train, the Snowpiercer, run by reclusive transportation magnate Wilford. The passengers on the train are segregated, with the elite in the extravagant front cars and the poor crammed into squalid tail compartments overseen by armed guards. Urged by his mentor Gilliam, Curtis Everett and his second-in-command, Edgar, lead the tail passengers in a revolt. They discover that the guards have no ammunition and overwhelm them, freeing Namgoong Minsoo, a captive security specialist. For his assistance, they bribe him with Kronole, an addictive drug made from industrial waste. Namgoong also insists that his clairvoyant daughter, Yona, be freed. Curtis and his fellow revolutionaries discover that the protein bars they were being fed were made of dead cockroaches. Namgoong helps the tail mob advance, but they face guards armed with melee weapons and overseen by Minister Mason. Edgar is held hostage, but Curtis allows him to be killed to capture Mason, forcing her to order the remaining guards to surrender. The tail mob stays back, holding the guards captive, while Curtis takes Mason, Namgoong, Yona, skilled fighter Grey, and Tanya and Andrew (two parents who had their children taken from them) towards the front of the train. Curtis's group travels through several opulent cars. Namgoong and Yona recognize a landmark outside and speculate that the ice may be thawing more and more with every passing year. The group reaches a schoolroom, where a teacher is indoctrinating the children on Wilford's greatness. A bald man brings eggs for the children to celebrate the train's eighteenth circumnavigation of the Earth. Then the bald man goes to the tail army and shoots them with automatic firearms hidden under the eggs. The captured guards are freed, as is Mason's henchman, Franco. The teacher, who received a gun from the bald man, kills Andrew before Grey kills her. Franco broadcasts to the classroom his execution of Gilliam, which prompts Curtis to execute Mason in turn. Curtis's group moves on, but Franco catches up with them, killing Grey and Tanya. Franco is then seemingly killed by Curtis and Namgoong. In the last compartment before the engine, Namgoong reveals that he collected the Kronole to use it as an explosive to escape the train with Yona, believing they can now survive outside, pointing out the melting ice. Curtis explains that in the early days of the train, the tail section resorted to cannibalism. Edgar was an infant when Curtis killed his mother, and Curtis was going to eat him when Gilliam offered his severed arm instead, stopping the bloodshed. Curtis wants to confront Wilford for causing such horrors. Wilford's assistant, Claude, emerges from behind the engine room door to invite Curtis inside. Curtis meets Wilford and, to his shock, learns that he and Gilliam conspired to stage Curtis's rebellion to reduce the tail section's population to sustainable levels. After ordering the execution of most of the tail section residents, Wilford offers Curtis his position leading the train. Curtis appears ready to accept as Yona overpowers Claude, rushes in, and asks for a match. In desperation, she pulls open a floorboard to reveal Tanya's son, Timmy, who has been enslaved to work as a replacement for a broken machine part. Appalled, Curtis pummels Wilford and rescues Timmy from the machinery, losing his arm in the process. Andy, Andrew's missing son, crawls out of a nook and climbs into the engine core despite Curtis's pleas. Curtis gives Yona the match to light the fuse for the Kronole bomb, while Namgoong fights and kills Franco, who followed them. Damaged by the fighting, the door to the engine room cannot be closed, forcing Curtis and Namgoong to use their bodies to protect Yona and Timmy from the blast. The explosion triggers an avalanche that derails the train and wrecks it. Curtis and Namgoong are unresponsive, so Yona and Timmy escape the wreckage. They see a polar bear in the distance, indicating that life exists outside the train and has not died out, as they were always led to believe.

In the 2020s, boxing between human fighters has been replaced with robots. In Texas, former boxer Charlie Kenton owns the robot Ambush until it is destroyed in a fight against a bull belonging to promoter and carnival owner Ricky. Having bet money he did not have with Ricky that Ambush would win, Charlie absconds before Ricky can collect. After the fight, Charlie learns his ex-girlfriend died, and he must attend a hearing about their 11-year-old son Max, whom he hasn't seen since birth. Max's maternal aunt Debra and her husband Marvin seek full custody. Charlie agrees to give up custody of Max for money, while Marvin negotiates that Charlie keeps custody for three months during their vacation. Settling into a gym owned by Bailey Tallet, the daughter of Charlie's former boxing coach, Charlie uses half the money to acquire the once-famous World Robot Boxing (WRB) robot Noisy Boy. He and Max take Noisy Boy to Crash Palace, an underworld boxing arena run by his friend Finn, where Noisy Boy is destroyed against robot boxer Midas. While searching for replacements in a junkyard and then sliding down a cliff, Max discovers Atom, an obsolete, dilapidated, but mostly intact sparring robot that breaks Max's fall and saves his life. Atom is designed to endure damage with a rare "shadow function" program, which mirrors and memorizes the handler's or opponent's movements. Charlie pits Atom against the robot Metro at Max's request, and the junkyard bot surprisingly comes out on top. Max integrates Noisy Boy's voice command hardware with Atom and convinces Charlie to optimize Atom's movements. Altogether, Charlie's boxing experience and Atom's shadow function build a winning streak that leads to Charlie being offered a WRB fight between Atom and the national champion, Twin Cities. The fight starts with Atom on the attack, but Twin Cities quickly takes the offensive. Charlie notices a hitch (a brief delay) whenever Twin Cities throws a right punch, and he exploits this to win by knockout. Elated by their success, Max challenges the undefeated fighting robot and Real Steel Champion of the World, Zeus. After the fight, Ricky and two henchmen attack Charlie for bailing earlier and rob him and Max of their winnings, prompting a defeated and dejected Charlie to return Max to Debra. When Charlie tries to convince an upset Max that he is better off without him, the boy reveals that all he ever wanted was for him to fight for him and be there as a father. After Max leaves, Charlie returns to Tallet's Gym and talks with Bailey. She persuades him to reconcile with Max, and Charlie convinces Debra to allow Max to come to the fight he set up with Zeus. As the fight begins, Zeus dominates the first round, but Atom manages to survive, stunning the audience. Ricky, who bet with Finn on Atom losing within the first round, tries to leave but is cornered by Finn and his bookmakers. As the fight continues, Atom lands multiple punches and withstands further attacks but makes no definitive progress. Late in the fourth round, Atom's voice-response controls are damaged, forcing Charlie to fight Zeus with Atom's shadow function for the fifth and final round, in which Charlie wards off Zeus with a rope-a-dope tactic long enough to deplete its power core, allowing Atom to begin a counterattack against an exhausted Zeus. With Zeus' programmers unable to compensate, the designer, Tak Mashido, intervenes and controls Zeus manually. Zeus is soundly beaten but narrowly avoids losing by knockout and wins by a judge's decision. Despite the match result and remaining undefeated, Zeus is left critically damaged, and Mashido's group is humiliated by the near-loss. The cheering crowd triumphantly labels Atom the "People's Champion," and Max and Charlie celebrate.

After a prologue (La llave) imitating an Eastern European black-and-white short film, the story is told in a retrospective way. P. Tinto was born obsessed with building a big family and soon enlists a blind girl, Olivia, in his big life project. However, despite his best intentions, the couple is unable to have kids due to their incompetence to understand the sexual innuendo of the adults and they spent the most of their lifes trying to have kids just by pulling the suspenders in and out and singing "tralari, tralari". After several years without having any kid, the now elder couple decide to pray for a miracle and that same night a couple of Martians ends up stranded in their door. P. Tinto, thinking they are children due to their short stature, decides to adopt them and treat them as kids, despite their protests and their adult behavior. Some time later, while watching a video reel about a big family favoured by the government and the need to adopt African orphans, P. Tinto decides to adopt one, but his adoption form goes flying to the hands of Pancho Jose, a man that just escaped from a Polish madhouse and armed with a big butane cylinder. Along with him, a nationalist contractor called Usillos that was giving him a ride, has his car broken in front of the Tinto´s house. Mistaken as an African orphan, Pancho is adopted by the couple, while Usillos is contracted by P. Tinto to rebuild his library to adapt it as a new room for Pancho, Usillos accepts the job after learning that an UFO machine is hidden in the house. Pancho Jose bonds with the Martians after learning that the UFO is also a time machine and he decides to help them to fix it so he can come back in time to save his mother from being crushed by a big box of cheese and prevent a sad chain of events to happen in his life. However, P. Tinto has another plans for Pancho when he learns the contract with the factory´s biggest client, The Vatican, is about to be cancelled, and tries to lure Panchito into the business. While Panchito tries to propose a new product (pizza) for the business, P. Tinto gets angry and locks his son in the attic, where he learns that the UFO got broken during a test run in a weird accident. P. Tinto decides to use his son´s idea, but is quickly rejected by the priest of the town that decides to lure any of the "kids" to the church, enlisting Jose Ramon, one of the Martians, in the process. Ramon, enlightened by faith, decides to become a priest and leave behind the idea to come back to Mars. Meanwhile, Pancho Jose seduces Olivia (that complained a lot about a pain in her low stomach) and the woman dances the next morning in a burst of happiness just to be run over by a train. Pancho Jose, frustrated over the outcome of the last events, decides to rebuild the time machine using Usillo´s truck. Usillos, having enough information about the UFO, reports is to the NASA, but when the investigators arrive, they took Usillos instead, as they find him dressing with his UFO gadgets, his thumb incredibly swollen and completely crazy. Pancho Jose manages to complete the machine and says goodbye to P. Tinto. He leaves with the other Martian, just to reveal that he wasn´t alone bringing with him a midget friend from the madhouse he brought in his luggage that turned also to be a Martian. They came back to time to save Pancho´s mother and reunite her with his past self. This leads to a sequence of changes in the time lapse, reverting the death of Olivia and leading an African orphan to find the house of P. Tinto that is on the roof waiting for a miracle. In a mid-credits scene, it is revealed that the stranded Martian was found in the road and, while he insisted that he is an alien, is again mistaken as a kid and adopted by a big family along with another African orphan. At the end of the credits, we see Olivia running happily in the meadows.

In 1988, amidst war between the United States and an alliance of China and the USSR, Manhattan has been converted into a maximum security prison to address a 400% increase in crime. In 1997, while flying President John Harker to a peace summit in Hartford, Air Force One is hijacked by a terrorist group. The President is handcuffed with a briefcase and put into an escape pod that drops into Manhattan as the aircraft crashes. Police, led by Commissioner Bob Hauk, are dispatched to rescue the President. Romero, a subordinate of the Duke of New York, warns Hauk that the President has been captured and will be killed if further rescue attempts are made. Meanwhile, decorated war hero and former Special Forces soldier Snake Plissken is about to be imprisoned in Manhattan after being convicted of robbing a Federal Reserve Depository. Snake accepts a deal from Hauk in which he will be pardoned in exchange for rescuing the President in time for the summit. To ensure his cooperation, Hauk has Snake injected with micro-explosives that will sever his carotid arteries in 23 hours. If Snake is successful, Hauk will neutralize the explosives. Snake uses a stealth glider to land atop the World Trade Center, then follows the President's tracking device to a vaudeville theater, only to find the tracker on the arm of a vagrant. Inspecting the escape pod, Snake is ambushed by starving underground raiders, and his radio is destroyed. He is rescued by "Cabbie," a fan of Snake's who drives a taxi. Cabbie takes Snake to Harold "Brain" Hellman, an adviser to the Duke and a former associate of Snake. An engineer, Brain has established a gasoline refinery fueling the city's remaining cars; he tells Snake that the Duke plans to lead a mass escape across the 69th Street Bridge, using the President as a human shield. Snake forces Brain and his girlfriend Maggie to lead him to the Duke's hideout at Grand Central Terminal. Snake finds the President but gets shot in the leg with a crossbow bolt and is overpowered by the Duke's men. While Snake is forced to fight Duke's champion, Slag, in a match to the death, Brain and Maggie kill Romero and flee with the President. Snake kills Slag and finds the trio trying to escape in the glider. Inmates drop the glider off the roof, forcing the group to street level, where the Duke and his followers confront them. Cabbie arrives and offers to take them across the bridge. He reveals that he bartered with Romero for a cassette tape that contains information about nuclear fusion, intended to be an international peace offering. The President demands the cassette, but Snake refuses to hand it over. The Duke gives chase, setting off mines as he tries to catch up. Brain guides Snake, but they hit a mine, and Cabbie is killed. As they continue on foot, Brain accidentally stumbles onto another mine. A distraught Maggie sacrifices herself to slow the Duke. Snake and the President reach the containment wall, and guards hoist the President up. The Duke opens fire, killing the guards before Snake subdues him. As the rope is lifting Snake, the Duke attempts to shoot him, but the President takes up a dead guard's rifle and kills the Duke. Snake is hoisted to safety, and Hauk's doctor neutralizes the explosives in his neck. As the President prepares for a televised speech to the leaders at the summit meeting, he off-handedly thanks Snake for saving him and offers only half-hearted regret for the deaths of Cabbie, Brain and Maggie; Snake walks away in disgust. Hauk offers Snake a job as his deputy, but he keeps walking. The President's speech commences, and he plays the cassette. To his embarrassment, it only plays Cabbie's favorite song, " Bandstand Boogie ". As Snake walks away free, he pulls the real cassette from his pocket and destroys it.

In the Spanish countryside, a middle-aged man named Héctor and his wife Clara live in a home that they are renovating. Héctor scans the forest behind their house with binoculars and sees a young woman take off her T-shirt, exposing her breasts. When his wife goes shopping, he investigates and finds the woman on the ground, naked and unconscious. He is stabbed in the arm by a mysterious man with bloody bandages on his face. Fleeing and breaking into a mysterious nearby building, Héctor contacts a scientist by walkie-talkie, who warns him of the bandaged man and guides him to his location, promising safety. With the bandaged man just outside, the scientist convinces Héctor to hide inside a large mechanical device. When Héctor leaves the machine, he discovers that he has traveled approximately an hour back in time. The scientist explains that the machine is an experimental time machine and refers to Héctor as "Héctor 2". The scientist tells Héctor 2 that they need to stay where they are and let events unfold. Despite the scientist's warning, Héctor 2 drives off in a car, passing a cyclist, who he recognizes as the woman Héctor 1 saw in the forest. Héctor 2 chases the woman, only to be run off the road by a van, cutting his head, which he wraps using the bandage from his arm wound. He then realizes the bandaged man from before is himself. The woman approaches to see if he is all right. Héctor 2 replicates events by making the woman undress in view of Héctor 1. When she runs away, Héctor 2 catches her, inadvertently knocking her out. Héctor 2 lays her out naked on the ground and then stabs Hector 1 in the arm when he arrives. The woman escapes. Héctor 2 returns to his home, where he hears a scream and chases a woman through his house and onto the roof. When Héctor 2 attempts to grab her, she slips and falls to her death. Seeing the body from the roof, Héctor 2 is horrified, believing he has killed his own wife. Héctor 2 contacts the scientist over the walkie-talkie and convinces him to lure Héctor 1 to the lab with warnings that he is being pursued. Driving to the lab, Héctor 2 insists that he must travel back one more time, despite the scientist revealing that there is a Héctor 3, who told him he must stop Héctor 2 from doing just that. After removing his bandages, Héctor 2 convinces the scientist to send him back several seconds before Héctor 2 initially appears. This causes him to become Héctor 3, who uses a van to run Héctor 2 off the road, but crashes as well, knocking himself out. Upon waking, Héctor 3 informs the scientist he has failed to stop Héctor 2. Héctor 3 encounters the woman again, startling her into screaming, though she does not recognize him as her assailant. Since Héctor 2 has heard her scream, Héctor 3 and the woman flee to Héctor's house. They become separated. Héctor 3 finds and hides his wife, then realizes what has to happen / will happen / has already happened. He finds the woman, cuts her ponytail off, gives her his wife's coat and tells her to hide upstairs. Héctor 2 chases her onto the roof. Héctor 3 sits on his lawn with his wife as Héctor 2 accidentally kills the woman, then drives off – heading back to the lab to become Héctor 3. Emergency vehicles are heard approaching in the distance.

David is escorted to a hotel after his wife leaves him for another man. The hotel manager reveals that single people have 45 days to find a partner or they will be transformed into an animal of their choice (the dog accompanying David is his brother Bob). David is set on becoming a lobster, should he fail. David makes the acquaintance of Robert, a man with a lisp, and John, a man with a limp. Guests are fixated on finding a mate with whom they share superficial traits such as minor ailments, which they believe to be the key to compatibility. The hotel has many rules and rituals: masturbation is banned, but sexual stimulation by the hotel maid is mandatory, and guests attend dances and watch propaganda extolling the advantages of partnership. Residents can extend their deadline by hunting and tranquilizing the single people who live in the forest, with each captured " loner " earning them an additional day. On the way to a hunt, a woman with a fondness for butter biscuits offers David sexual favours, which he declines. She tells him that if she fails to find a mate, she will kill herself by jumping from a hotel window. John wins the affections of a woman with constant nosebleeds by purposely smashing his nose in secret. They move to the couples' section to begin a month-long trial partnership. David later decides to court a notoriously cruel woman who has tranquilized more loners than anyone else. Their initial conversation is accompanied by the screams of the biscuit-loving woman, who has injured herself by jumping from a first floor window. David pretends to enjoy the woman's suffering to gain the heartless woman's interest. He later joins her in a hot tub where she feigns choking on an olive to test him. Noticing that he makes no attempt to help her, she decides that they are a match, and the two are shifted to the couples' suite. David wakes up one morning and finds she has killed Bob. As David tearfully mourns him, she concludes that their relationship is a lie and attempts to drag him to the hotel manager to have him turned into the "animal that no one wants to be" as punishment. He escapes and, with the help of a sympathetic maid (later revealed as a mole working for the loners), tranquilizes his partner and transforms her into an unspecified animal. David escapes the hotel and joins the loners in the woods. In contrast to the hotel, they forbid any kind of romance, which is punishable by mutilation. David, who is short-sighted, begins a secret relationship with a woman who is also short-sighted. They develop a gestural language they use to communicate. They are taken on covert missions to the nearby city, where their cover requires them to appear as husband and wife, which they secretly enjoy. Because they have the required superficial traits in common and genuinely enjoy each other's company, they make a plan to leave the loners and rejoin society. The loners launch a raid to sabotage the hotel. David tells the woman with nosebleeds that John has been faking his. Other loners hold the hotel manager and her husband at gunpoint, tricking him into shooting his wife to save himself, but the gun is not loaded. They leave the couple to face each other. The leader of the loners obtains the short-sighted woman's journal and discovers David's plan to escape with her. The leader and the maid take the woman to the city, ostensibly to have an operation to cure her short-sightedness, but instead have her blinded. The woman attempts to stab the leader, but the leader uses the maid as a human shield and pretends to die when the woman stabs the maid to death. David and the woman try to find something else that they have in common, to no avail. One morning, David overpowers the leader, leaving her tied up in an open grave to be eaten alive by wild dogs. He and the blind woman escape to the city and stop at a restaurant. David goes to the restroom and hesitantly prepares to blind himself with a steak knife.

In 1979, Deputy Sheriff Jack Lamb of Lillian, Ohio and his 14-year-old son Joe mourn the death of wife and mother Elizabeth in a workplace accident. Jack blames Elizabeth's co-worker Louis Dainard for the accident, as Dainard had a hangover, resulting in Elizabeth having to cover his shift. Joe clings to his mom's memory in the form of a locket. Four months later, Joe's friend Charles is making a zombie movie for a Super 8 film competition. He enlists Joe's help along with friends Preston, Martin, and Cary, as well as Dainard's daughter, Alice. Though their fathers are opposed to their friendship, Joe and Alice become close. One night while they film at a train depot, a pickup truck rams an approaching train head-on, derailing it (which they capture on film) and destroying the depot. After being scattered by the fiery chaos, the kids regroup and find crates of strange white cubes amid the wreckage, and discover the truck driver to be their biology teacher Dr. Woodward. Gravely injured, he warns them at gunpoint to forget what they have seen. They flee, as a convoy from the local Air Force base, led by Col. Nelec, arrives. Nelec finds an empty Super 8 film box. In the following days the town experiences strange events: dogs run away, several townspeople go missing, the electrical power fluctuates, and electronic items are stolen. Jack approaches Nelec, but Nelec arrests him. Nelec orders flamethrowers to start a wildfire as an excuse to evacuate the residents to the base. Watching their footage, Joe and Charles notice a large creature escaping the train. In a military hospital, Nelec questions Woodward about the creature. After Woodward rebukes him, Nelec has him killed with a lethal injection. Louis and Alice get into a fight and she attempts to flee on her bike, Louis chases after her in a car but gets into an accident, as Alice is fleeing, the creature abducts her. Louis, while in recovery from his car accident, tells Joe the creature has abducted Alice. Joe, Charles, Martin, and Cary persuade Jen, Charles's older sister, to flirt with Donny so he can get them into town to rescue Alice. Breaking into Dr. Woodward's trailer, they learn of his work as a former government researcher. In 1963, the Air Force captured a crash-landing alien. Its spacecraft, composed of the white cubes, allowed it to shape-shift. While being experimented on, the alien established a psychic connection with Woodward, convincing him to help it escape Earth. His effort was sabotaged by Nelec who discredited, and discharged Woodward. Nelec captures the kids, but the alien kills Nelec and his airmen, allowing them to escape. Jack escapes and agrees with Louis to put aside their differences to save their kids. The military attacks the alien, but their hardware goes haywire in its presence, resulting in significant collateral damage. Joe and Cary find a massive tunnel system under the town. The missing townsfolk, including Alice, are hanging unconscious from the ceiling of a cavern. Here, the alien is creating a device, constructed from the missing electronics, and attached to the base of the water tower. Using firecrackers as a distraction, Joe frees Alice and the others. The alien grabs Joe, who quietly speaks to it, convincing that it could "still live" while bad things happen. Establishing an emotional connection between the two of them, the alien realizes that not all humans are as bad as Nelec and spares him, allowing them to return to the surface. Everyone watches as metal objects from the town are pulled to the top of the tower by an unknown force. The white cubes reassemble to create a spaceship and, as the alien enters it, Elizabeth's locket is drawn toward the tower. Joe lets it go, completing the ship. As the ship rises into space, he takes Alice's hand. The short film the children were making in Super 8 runs at the end of the movie beside the credit roll. In it, Charles's character asks for his short film "The Case" to be picked for a local film festival before being attacked by a zombie played by Alice.