A man and his young son struggle to survive after an unspecified catastrophe results in an extinction event, which causes the death of all plant life and virtually all animal life. The man and boy travel on a road to the coast in hope that they can find safe haven, scavenging for supplies in their journey, and avoiding roaming cannibalistic gangs armed with guns. Years earlier, the man's wife gives birth to their son shortly after the catastrophe and she gradually loses hope. When the man shoots an intruder using one of three bullets they have saved for their family as a last resort, she accuses him of wasting the bullet deliberately to prevent her suicide. Removing her coat and hat in the freezing cold, she walks into the woods, never to be seen again. In the present, after shooting a member of a gang of cannibals who stumbles upon them, the man is left with only one bullet. Exploring a mansion, he and the boy discover people locked in the basement, imprisoned as food for their captors. When the cannibals return, the man and his son hide. With discovery imminent, the man prepares to shoot his son, but they flee when the cannibals are distracted by the escaping captives. Further down the road, the man and boy discover an underground shelter full of canned food and supplies. They feast and bathe. When they hear noises above, including a dog, the man decides it is too dangerous to remain and they move on. They meet a near-blind old man, and the son persuades the father to share food with him. Later, the two encounter a campsite with infants' skulls on pikes. They are hurriedly moving away from this campsite when they witness a cheering mob descend upon a mother and her son in a meadow, and flee as the mob murders the two. At the coast, the man leaves the boy to guard their possessions while he swims out to scavenge a beached ship. The boy falls asleep and their supplies are stolen. The man chases down the thief and takes everything from him, even his clothes. This distresses the boy so much the man turns back and leaves the clothes and a can of food for the thief, who has since disappeared. As they pass through a ruined town, the man is shot in the leg with an arrow. He kills his ambusher with a flare gun he found on the ship and finds the archer's female companion in the same room. The man thinks the archer and woman were following them, but she claims it was the other way around. He leaves her weeping over the body. Weakened, the man and boy abandon their cart and most of their possessions. The man's condition deteriorates and eventually, he dies. The boy is approached by a man with his wife, two children, and dog. The wife explains they have been following the boy and his father for some time and were worried about him. The father convinces the boy he is one of the "good guys" and takes him under his protection.

Okwe, a doctor in his home country (not initially named) who was forced to flee after being falsely accused of murdering his wife, lives in the United Kingdom as an undocumented immigrant. He drives a cab in London during the day and works at the front desk of a hotel at night, which is staffed by other immigrants, both documented and undocumented. He is pressed to treat other poor immigrants, including fellow cab drivers with venereal diseases, with scarce supplies provided by his friend Guo Yi, an employee at a hospital mortuary. Juliette, a sex worker who regularly conducts her business at the hotel, informs Okwe about a blocked toilet in one of the rooms, and he fishes out a human heart. The manager of the hotel, Juan, runs an illegal operation at the hotel wherein immigrants swap kidneys for forged passports. After learning of Okwe's past as a doctor, Juan pressures him to join his operation as a surgeon, but Okwe refuses. Senay is a Turkish Muslim seeking asylum who also works at the hotel as a cleaner. Her immigration status allows her to stay in the UK, provided she does not work; the hotel is a perfect cover because she is not named on its books. She allows Okwe to sleep on her sofa when she is not home, as she is from a conservative culture where men and women who are not married do not spend the night together under the same roof. After Senay is visited by Immigration Services, who inspect the hotel after finding a book of matches in her flat, Okwe prevents the officials from intercepting her. No longer able to work at the hotel, Senay begins working in a sweatshop making clothes, which is also raided by officials looking for undocumented immigrants, who the manager gets rid of. The manager allows Senay to keep her job and not report her to the authorities in return for her performing oral sex on him; she initially complies before proceeding to bite him. Okwe finds her a place to stay at the hospital mortuary, while Senay asks him to accept Juan's proposition in his organ business to raise money to travel to America. In desperation, Senay offers her kidney to Juan for a passport; Juan accepts the deal on condition he takes her virginity as well. Senay is later provided with a morning-after pill by Juliette. After learning of Senay's plan, Okwe agrees to perform the operation to ensure her safety, but only if Juan provides them both with passports under different names. After Juan delivers the passports, Okwe and Senay drug him, surgically remove his kidney, and sell it to Juan's contact. Okwe plans to use his new identity to return to his young daughter in Nigeria, and Senay plans to start a new life in New York. Before they part at Stansted Airport, they mouth the words "I love you" to each other, and she gives him her cousin's address in New York. Senay boards her plane, and Okwe calls his daughter long-distance to tell her he is finally coming home.

An ancient Buddha statue named Ong-Bak is kept in the village of Ban Nong Pradu in rural northeastern Thailand. The villagers fall in despair after thieves from Bangkok desecrate the statue Ong-Bak and take the head with them. Ting, a resident and Muay Thai expert, volunteers to travel to Bangkok to recover the stolen head. Ting's only lead is Don, a drug dealer who attempted to buy an amulet in Nong Pradu earlier. Upon arriving in Bangkok with a bagful of money donated by the village, Ting meets his cousin Humlae, who has dyed his hair blond and begun calling himself "George." Humlae and his friend Muay Lek are street-bike racing hustlers who make a living out of conning yaba dealers. Reluctant to help Ting, Humlae steals Ting's money and bets it in an underground fighting tournament at a bar on Khaosan Road. Ting tracks down Humlae and gets his money back after stunning the crowd by knocking out the champion, where his extraordinary skill grabs the attention of Komtuan, a grey-haired crime lord who uses a wheelchair and needs an electrolarynx to speak. Don is the one who ordered Ong-Bak's head stolen to sell it to Komtuan, who sees no value in it and orders him to dispose of it. The next day, Humlae and Muay Lek are chased all over town by drug dealer Peng and his gang after a botched baccarat game scam at an illegal street gambling booth. Ting fights off most of the thugs and helps Humlae and Muay Lek escape in exchange for helping him find Don. They return to the bar, where Ting wins the respect of the crowd after defeating three opponents consecutively. The trio find Don's hideout, triggering a lengthy tuk-tuk chase. The chase ends at a port in the Chao Phraya River, where Ting discovers Komtuan's cache of stolen Buddha statues submerged underwater. After the statues are recovered by police, Komtuan sends his thugs to kidnap Muay Lek and tells Humlae to ask Ting to fight his bodyguard Saming near the Thai- Burmese border in exchange for Muay Lek and the Ong-Bak head. Ting is forced to throw the match against the drug-enhanced Saming, and Humlae throws in the towel. After the fight, Komtuan reneges on his promise to release Muay Lek and return the head, where he orders his henchmen to kill the trio. Ting and Humlae subdue the thugs and head to a mountain cave, where Komtuan's men are cutting a giant Buddha statue. Ting defeats the remaining thugs and Saming but is shot by Komtuan, who attempts to destroy the Ong-Bak head with a sledgehammer. Humlae protects it with his body, taking the brunt of the hammer blows. The giant Buddha statue head suddenly falls, crushing Komtuan to death and critically injuring Humlae. With his dying breath, Humlae gives the Ong-Bak head to Ting and asks him to look after Muay Lek. The head is returned to Ban Nong Pradu. Humlae's ashes, carried by an ordained monk, is brought to the village in a procession on an elephant's back while the villagers, Ting and Muay Lek celebrate the return of Ong Bak's head.

When 17-year-old Tanja Lorentzen is found murdered in the city of Tromsø, far up in the Norwegian Arctic, Kripos police officers Jonas Engström (Stellan Skarsgård) and Erik Vik (Sverre Anker Ousdal) are called in to investigate. Engström, formerly with the Swedish police, moved to Norway after being caught having sex with the main witness in one of his cases. Vik is nearing retirement age, and his memory is failing. Engström devises a plan to lure the murderer back to the scene of the crime, but the stakeout is blown and the suspect flees into the fog, shooting one of the Norwegian police officers in the leg. Unbeknownst to his unarmed colleagues, Engström carries a gun from his days in the Swedish police, who routinely carry firearms. Firing at what he believes to be the suspect, Engstrom accidentally kills Vik, who had mistakenly run right instead of left as ordered. Realizing that everyone assumes Vik was shot by the fugitive, Engström decides not to admit his culpability. When one of his colleagues, Hilde Hagen (Gisken Armand), is assigned to investigate Vik's death, Engström becomes worried about ballistic fingerprinting and tampers with evidence to support his story. Haunted by guilt and unable to sleep with the midnight sun of the Arctic, Engström becomes increasingly unhinged and starts hallucinating about Vik. Engström learns from one of Tanja's friends that she had been seeing Jon Holt (Bjørn Floberg), a crime novelist. He correctly deduces that Holt killed Tanja, but Holt reveals that he saw Engström shoot Vik. The two decide to frame Tanja's boyfriend Eilert for her murder, with Engström later planting Holt's gun under Eilert's bed and Holt giving testimony about Eilert being abusive. However, Hagen is not convinced, and when new evidence emerges, Engström knows that it is only a matter of time until Holt is arrested. Engström tracks Holt to some waterfront properties that are slowly collapsing into the sea. Holt suspects that Engström has come to kill him and holds him at gunpoint, explaining how he killed Tanja in a fit of rage when she rejected his advances. Holt tries to flee across a pier, but the rotten floorboards give way and he falls into the water below, striking his head on the way down. He drowns as Engström watches. When Engström searches Holt's nearby house, he finds Tanja's dress, which Holt had removed before dumping the body. With Holt dead, and definitive proof he was the murderer, the case is closed. Just before he leaves town, Engström is visited by Hagen, who shows him a cartridge case found at the site where Vik was shot. She notes it is a Norma, which Engström confirms is a brand used by the Swedish police. Engström expects Hagen to arrest him, but instead she simply places the cartridge on a table and leaves. Engström drives out of town, his face and eyes showing great weariness, and he seems not to have recovered from his insomnia.

At a bistro in Montmartre, IRA operative Deirdre meets with two Americans, Sam and Larry, and a Frenchman, Vincent. She takes them to a warehouse where Englishman Spence and German Gregor are waiting. Conversations among the men reveal that they are former government and military agents who have become mercenaries. Deirdre briefs the group on their mission: to attack a heavily armed convoy and steal a large, metallic briefcase, whose content is never revealed. The team's first preparation task is to acquire firearms, which turns into an ambush; the team survives and gets the weapons. Deirdre meets with her handler, Seamus O'Rourke, who tells her that the Russian mafia is bidding on the briefcase and that the team must intervene to prevent them from winning. Spence is exposed as a fraud by Sam; he is dismissed by Deirdre, and the others continue their mission. Deirdre's team successfully ambushes the convoy at Villefranche-sur-Mer and pursues the survivors to Nice. During the gunfight, Gregor steals the case and replaces it with explosives in an attempt to sabotage the others. He attempts selling it to the Russians, but his contact betrays him; Gregor kills the contact and has Mikhi – the Russian mobster in charge of the deal – agree to another meeting. The team tracks Gregor through one of Sam's old contacts and corners him in the Arles Amphitheatre during his meeting with two of Mikhi's men. Sam chases Gregor, who flees but is caught by Seamus. Deirdre and Vincent confront the two Russian hoods, prompting a shootout. Sam arrives to help, killing one, but is injured by a ricochet from the other. Seamus kills Larry and escapes with a reluctant Deirdre and the captured Gregor. Vincent takes Sam to a villa that is owned by his friend Jean-Pierre. After removing the bullet and letting Sam recuperate, Jean-Pierre compares Sam's situation to the tale of the 47 Ronin. Vincent asks Jean-Pierre to help them find Gregor and the Irish operatives. In Paris, Gregor is persuaded through violent interrogation to return the case to Seamus and Deirdre. After retrieving it from a post office, they are pursued by Sam and Vincent in a high-speed chase. Vincent shoots out their tire, sending their car off an overpass. Gregor escapes with the case while road workers rescue Deirdre and Seamus from the burning vehicle. Doubtful of where to go next, Sam and Vincent decide to track down the Russians after discovering that the decoy case that Gregor used in his theft of the original is used for carrying ice skates; one of Jean-Pierre's contacts informs them that the Russians may be involved with figure-skater (and Mikhi's girlfriend) Natacha Kirilova, who is performing at Le Zénith. During Natacha's show, Mikhi meets with Gregor, who says that a sniper in the arena will shoot Natacha if Mikhi betrays him. Mikhi kills Gregor and takes the case, allowing Natacha to be killed by the sniper. Amid the ensuing chaos from Natacha's shooting, Sam and Vincent leave the arena in time to see Seamus kill Mikhi and steal the case. Sam and Vincent split up; Vincent pursues Seamus but is wounded in a gunfight. Sam finds Deirdre waiting in a getaway car and convinces her to leave, after explaining that he is still in the CIA and is after Seamus, not the case. As she drives away, Seamus is forced to return to the arena as Sam gives chase. Seamus ambushes Sam but is shot dead by Vincent before Seamus can kill Sam. Sam and Vincent have coffee in the bistro where they first met. A radio broadcast announces that a peace agreement between Sinn Féin and the British government has been reached, partially as a result of Seamus's death. Sam keeps glancing at the door as patrons enter, but Vincent convinces Sam that Deirdre will not be coming back. They shake hands and part ways, but not before Vincent asks what was in the case. Sam replies that he does not remember. Sam drives off with his CIA contact as Vincent pays the bill and leaves.

Force Recon Scout Snipers Gunnery Sergeant Bob Lee Swagger and his spotter Donnie Fenn provide overwatch for a black ops mission in Ethiopia. The mission is successful, but while covering the retreat of friendly forces, an enemy attack helicopter assaults their position, resulting in Fenn's death. The CIA officer supervising the operation disavows the mission and strands them in enemy territory without any backup, though Swagger survives. Three years later, a retired Swagger is approached by Colonel Isaac Johnson to seek his help in preventing a possible assassination attempt on the President during a public event. Swagger identifies Philadelphia as the best location for the act, and pinpoints likely sniper spots. Swagger joins Johnson at an overwatch position during the event, where a sniper kills Ethiopian Archbishop Desmond Mutumbo. Officer Stanley Timmons, a Philadelphia Police Department officer bribed by Johnson, shoots Swagger, who falls through a window. Swagger disarms rookie FBI Agent Nick Memphis and warns him about Timmons, before jumping into the Delaware River and escaping under a ferry. Soon, news reports are released naming Swagger as the assassin and that he used his CheyTac M200 sniper rifle to kill Mutumbo. Evading authorities, Swagger travels to Kentucky and meets Fenn's widow, Sarah, who treats his injuries. Memphis grows suspicious of the unusually rapid conclusions, exacerbated by Timmons' odd death off-duty during an alleged mugging, begins his own investigation and realizes that the assassination was conducted with a remotely controlled gun. Sarah and Swagger discreetly feed Memphis information, furthering his investigation until he catches Johnson's attention, who orders his men to kidnap and kill Memphis. In captivity, Memphis is strapped with a brace that could force him to shoot himself, while his abductors force-feed him water in order to get him to urinate the ruphylin from his system. Before they can stage Memphis' suicide, Swagger kills them, releases Memphis and requests his help bringing down Johnson. The two travel to Tennessee and meet with firearms expert Mr. Rate, who explains paper-patching can be used to confuse ballistic fingerprinting and deduces that the only other person alive capable of making such a long-range shot is the crippled Serbian sniper Mikhaylo Sczerbiak, whom Swagger has unawarely met when working for Johnson. Swagger concludes that he was used to conduct reconnaissance for the wheelchair-using Sczerbiak, who performed the actual assassination remotely. At the same time, Sarah's connection to Swagger is uncovered, and she is abducted by Payne. In Virginia, Swagger and Memphis infiltrate Sczerbiak's estate, who reveals Johnson works for U.S. Senator Charles Meachum on behalf of oil conglomerates exploiting developing nations for profit. Swagger and Fenn had unknowingly covered PMCs who massacred an entire village on the Eritrea–Ethiopia border to make way for pipelines, and were deliberately abandoned as part of the cover-up. Johnson then ordered Sczerbiak to assassinate Mutumbo, who was going to discuss the massacre during his speech, to prevent Johnson's crimes against humanity from being revealed to the public. Sczerbiak also informs Swagger about Sarah's abduction, and then commits suicide as mercenaries close in on the estate. With Sczerbiak's confession recorded, Swagger and Memphis fight their way out and escape to Montana, tip off the FBI, and arrange a private meeting with Meachum and Johnson. Johnson, Meachum, and their men arrive at the meeting point on a snowy mountaintop, with Sarah held hostage. Memphis acts as a decoy, allowing Swagger to eliminate Johnson's sharpshooters and rescue Sarah, in which Sarah guns down Payne after the hell he put her through. Meachum cryptically implies he is not the only politician involved and arrogantly tells Swagger to give up. Deducing that the proof will get them murdered as witnesses, Swagger destroys the recording as the FBI arrests him. Swagger requests a plea hearing with United States Attorney General Russert. With Memphis's assistance, Swagger reveals that his personal rifles, including the supposed murder weapon, have all had their firing pins replaced, making them unusable. Johnson's men had stolen the rifle, retrieved a previous fired practice bullet and paper-patched it for Mutumbo's assassination, and planned to frame Swagger. Swagger's name is cleared, and Memphis also provides Russert with evidence cataloging Johnson's involvement in the village massacre and other crimes, but no legal action may be taken against him as the crimes fall outside U.S. jurisdiction. Afterwards, Russert casually hints that extrajudicial measures may be necessary to address the corruption before ordering Swagger's release. Boasting impunity at a private gathering, Meachum, Johnson and their associates discuss their next operation, but Swagger attacks the villa and kills them all. He frames the dead Johnson as the assailant, and ruptures the gas line causing a gas explosion before leaving the area with Sarah.

In Nightmute, Alaska, teenager Kay Connell is found beaten to death, her body scrubbed of forensic evidence and dumped naked in a landfill. At the request of the local chief, LAPD detectives Will Dormer and Hap Eckhart are sent to assist with the investigation. Ellie Burr, a young local detective who idolizes Dormer, is assigned as their guide. They question Kay's abusive boyfriend Randy Stetz, who admits he discovered Kay had a secret admirer but could not force her to reveal his identity. In private, Eckhart admits he is being pressured by an Internal Affairs investigation and will testify against Dormer in exchange for immunity. Kay's backpack is discovered at a shack near the coast and Dormer uses it to set a trap, but this backfires and the suspect flees into a heavy fog, shooting an officer in the leg. Giving pursuit, Dormer spots an unidentifiable figure and fires at them with his backup weapon after his sidearm jams. Grabbing a.38 caliber pistol the suspect dropped, Dormer rushes to the figure and discovers he has shot and killed Eckhart. The police assign blame to the suspect and Dormer does not dissuade them, knowing Internal Affairs will never believe the shooting was an accident due to Eckhart's pending testimony. Burr is assigned to the shooting investigation and finds the.38 bullet that pierced the officer's leg. That night, Dormer fires the.38 into an animal carcass, then retrieves and cleans the bullet. At the morgue, the pathologist gives him the 9 mm caliber bullet from Eckhart's body, which she doesn't recognize as very few people in the area own pistols. Dormer replaces it with the.38 bullet. When Burr believes the case is closed, however, Dormer's conscience refuses to let him sign off and he tells her to do another review, which causes her to notice inconsistencies in his statement. Dormer becomes plagued by insomnia, brought on by his guilt and further exacerbated by the perpetual daylight. He begins receiving phone calls from the killer, who witnessed Dormer shoot his partner. Questioning her estranged best friend, Dormer learns Kay was a fan of local crime writer Walter Finch, and realizes he was her secret admirer based on the alias she gave him. Dormer goes to Finch's apartment in a nearby village and breaks in, hiding the.38 in a heating vent. Returning home, Finch realizes someone is inside and escapes after a chase. Finch contacts Dormer again and arranges a public meeting on a ferry. Finch wants help shifting suspicion to Randy, offering to stay silent about the Eckhart shooting in return. Attempting to dissuade him from this, Dormer tells Finch he can't hide his relationship with Kay and gives advice on handling the inevitable police questioning. As Finch leaves the ferry, he reveals he has recorded the conversation. In another phone call, Finch admits he flew into a blind rage after Kay laughed at his romantic advances, stressing that her death was "an accident." Having lied that he lost the gun, Dormer suggests Kay's dress would be sufficient evidence to implicate Randy. The next day, Finch is questioned and mentions that Kay described Randy's abuse to him in her letters. Finch then claims Randy threatened Kay with a gun, and Dormer realizes his trap has again failed. Randy is arrested when the.38 is found in his house. Finch asks Burr to come to his lake house the next day to collect Kay's letters. Returning to the cabin, Burr discovers a 9mm shell casing. She reads her police academy thesis about one of Dormer's cases and realizes he carries a 9mm as a backup weapon. After trashing his room in an attempt to block the sunlight coming through the window, Dormer confides in the hotel clerk about the Internal Affairs investigation: he fabricated evidence against a pedophile he was certain had murdered one of his victims, and the conviction (among many others) would have been overturned had Eckhart testified. When he tries to justify this to himself, the clerk asks him if it's something he's willing to live with. Dormer breaks into Finch's apartment again and discovers Kay's letters. Realizing Burr is being lured into a trap, he rushes to Finch's lake house, where Finch reveals he has Kay's dress before knocking Burr unconscious. Dormer arrives and confronts Finch, but is disorientated from lack of sleep and overpowered before Burr revives and drives Finch off. She tells Dormer she knows he shot Eckhart, and he admits he is no longer certain it was an accident. Finch retrieves a shotgun from his boathouse and begins shooting; Burr returns fire while Dormer outflanks Finch. In a struggle Dormer wrestles the shotgun away, but Finch draws Burr's gun and they shoot each other, resulting in both of them being respectively wounded and killed. Attempting to comfort the mortally wounded Dormer, Burr moves to throw away the shell casing that proves his guilt. Dormer stops her, telling her not to lose her way as he did, before dying.

Sarah is picked up by her husband Paul and daughter Jessica after a whitewater rafting trip with her thrill-seeking friends Juno and Beth. Paul is distracted on the ride home, causing a car crash that kills both him and Jessica. Sarah awakens in the hospital and collapses after Beth tells her about their deaths. One year later, Sarah, Juno, and Beth reunite for a spelunking adventure in the Appalachian Mountains of North Carolina along with sisters Sam and Rebecca, and newcomer Holly. They hike to a mountain cave entrance and descend. Making their way through the caves, Sarah becomes stuck in a narrow tunnel, but manages to escape before it collapses, blocking the way back. Juno admits that she has led the group into an unexplored cave system instead of the mapped one they had filed with local authorities, which means that a rescue party would be unable to locate them. The group searches for an exit and discovers old climbing equipment and a cave painting that suggests a way out. Holly, thinking she sees sunlight, runs ahead but falls into a hole and breaks her leg. As the others help her, Sarah wanders off and sees a pale, humanoid creature drinking from a pool before it scampers away. Later, they come across a den of animal bones and are suddenly attacked by a creature they call a "crawler", which kills Holly. Sarah runs, but falls down a hole and is knocked unconscious. Juno, trying to stop Holly's body from being dragged away, kills a crawler with her pickaxe, but then accidentally stabs Beth in the neck after being startled. Beth grabs Juno's pendant as she collapses and a traumatized Juno flees. Sarah awakens in a den of human and animal carcasses to see Holly's body being mauled and eaten by crawlers. Juno discovers cave markings left by previous explorers pointing to a potential exit from the caves. She finds and saves Sam and Rebecca from a crawler, and Sam deduces that the creatures are blind and hunt by sound. Sarah finds a dying Beth, who reveals both that Juno stabbed her and that Juno's pendant was a gift from Paul, confirming Sarah's suspicions that Juno and Paul were having an affair. Beth begs Sarah to end her suffering, and Sarah reluctantly kills her with a rock. Sarah then encounters several crawlers and manages to kill them all, falling into a blood-filled pool in the process. Elsewhere, Juno, Sam, and Rebecca are pursued by a large group of crawlers. They reach a chasm, and Sam tries to climb across but is attacked by a crawler on the ceiling. It rips out her throat, but she stabs it before bleeding to death. Rebecca is dragged away and disemboweled as Juno flees. Juno later reunites with Sarah and lies about seeing Beth die. After defeating a group of crawlers near an exit, Sarah confronts Juno, revealing the pendant, and her knowledge of Beth's fate and the affair with Paul. She then stabs Juno in the leg with a pickaxe and leaves her to die as a horde of crawlers approaches. Juno removes the pickaxe from her leg to hold back the crawlers and is heard screaming as Sarah escapes. Sarah falls into a hole and loses consciousness. When she wakes, she sees sunlight and clambers up a bone-strewn slope to escape the cave. She reaches her car and speeds away, eventually pulling over to break down in tears. After a truck passes, she vomits out of the window. When she sits back up, she hallucinates seeing a bloodied Juno beside her, and screams. In the UK version, Sarah awakens, still in the cave, and has a vision of Jessica, smiling as the sounds of approaching crawlers grow louder.

In 2057, the Sun is dying and Earth is freezing. Eight astronauts aboard the starship Icarus II are sent on a last-chance mission to deliver and detonate a colossal stellar bomb intended to reignite the Sun. As the ship passes Mercury, it receives a distress beacon from Icarus I, the earlier mission that had disappeared seven years prior. Despite engineer Mace's objections, Captain Kaneda, acting on a recommendation from physicist Capa, decides to divert course in order to investigate and also to double the mission's success potential should the identical stellar bomb payload on the original ship prove operational as backup. Navigator Trey plots the new route but inadvertently overlooks realigning the ship's heat shields, damaging reflective panels that protect Icarus II from direct sunlight. Pilot Cassie angles the vessel into Mercury's shadow while Kaneda and Capa perform a spacewalk to repair the shield. The operation destroys two of the ship's communications towers, and reflected light incinerates the oxygen garden, reducing air reserves. When the emergency autopilot forces the ship back into its original alignment, Kaneda orders Capa to retreat and completes the final repair himself, moments before a wave of sunlight engulfs and kills him. Trey blames himself for losing Kaneda, and psychologist Searle sedates him after judging him a suicide risk. Now lacking sufficient oxygen to reach the Sun and deploy the bomb, Icarus II docks with Icarus I to salvage resources. Capa, Searle, Mace and communications officer Harvey board the derelict ship while Cassie and biologist Corazon remain on Icarus II with Trey. Although Icarus I appears largely operational, its mainframe has been sabotaged, preventing payload delivery. Mace finds a damaged entry log from Captain Pinbacker, badly burned and insisting their mission defies God, dated to roughly six and a half years earlier. On the observation deck, Searle discovers the charred bodies of the Icarus I crew, who were apparently exposed to unfiltered solar radiation. An explosive decoupling separates the ships and destroys Icarus I' s outer airlock, stranding the boarding team. With only one intact spacesuit and limited insulation, they decide that Capa, despite Harvey's protests, must take the suit because he is the only crew member able to arm the bomb. Searle stays behind to open the airlock, allowing the others to jettison back toward Icarus II using insulation for protection. Harvey misses the airlock and freezes to death, while Capa and Mace make it back. Left alone on Icarus I, Searle returns to the observation deck and exposes himself to unfiltered sunlight, killing himself. Back aboard Icarus II, Corazon calculates that the remaining oxygen will only sustain four people to the Sun. In order to preserve oxygen, the crew votes to have Mace kill Trey, but Trey has already committed suicide. Although the mission now seems possible, the ship's systems still detect five life signs. Capa investigates and finds Pinbacker alive now aboard Icarus II, having boarded during the docking and caused the decoupling. Pinbacker attacks Capa, traps him in an airlock, disables the ship by lifting its mainframes from coolant baths, and kills Corazon. Mace attempts to manually reset the mainframes, and succeeds with two, but the third crushes his leg and traps him in the coolant; freezing, he urges Capa to finish the mission. Capa pierces an interior hatch with a blowtorch and opens an exterior airlock so decompression tears away the obstruction and frees him, allowing him to deploy the payload. The bomb structure separates from Icarus II, and Capa makes a leap towards the payload as the ship is destroyed by solar radiation. Inside the payload, he finds a wounded Cassie, but Pinbacker confronts them again, claiming he has spent years "speaking to God," and subdues Capa; Cassie pulls Capa away, and he tears burned skin from Pinbacker's arm. As the bomb's gravity shifts, Capa reaches the controls and detonates the payload; in his final moments, spacetime distorts and he reaches out to the Sun's surface as it reignites. On Earth, Capa's sister and her children build snowmen on a frozen Sydney Harbour. As they listen to Capa's final transmission, the sun brightens and sunlight begins to shine down on them.

On an unspecified day during Christmas week, two years after the events of the previous film, John McClane is now a lieutenant with the LAPD, who arrives at Dulles International Airport to pick up his wife, Holly. He is met with hostility from airport police officer Vito Lorenzo, who issues him a parking ticket. Meanwhile, a plane carrying corrupt foreign military leader General Ramon Esperanza is headed to Dulles under extradition for using U.S. funds to buy drugs. Waiting to meet Esperanza's plane is disgraced former United States Army Colonel William Stuart and a group of ex-military sympathizers who supported Esperanza's actions. McClane follows two of Stuart's men into a baggage sorting area where a gun fight ensues. He kills one man, but the other escapes. With the help of his friend Sergeant Al Powell, McClane runs the dead man's fingerprints. They correspond to an American soldier who was listed as having died in a helicopter accident two years earlier. McClane reports his concerns to the ill-tempered airport police chief Carmine Lorenzo and air traffic control director Ed Trudeau, but neither believes him. Stuart and his men are operating out of a church on the outskirts of the airport. They cut all communications with incoming airplanes, disable runway lighting, and demand that Esperanza's plane be allowed to land without interference. Under Stuart's direction, Trudeau orders all planes in Dulles airspace held in the air despite their low fuel supplies. McClane becomes worried about Holly's plane, so enlists the help of airport janitor Marvin to fight back. Chief airport engineer Leslie Barnes decides to try using an unfinished antenna array to communicate with the airplanes. Lorenzo sends an airport SWAT team with him, but Stuart's men kill the officers and destroy the antenna. McClane saves Barnes and kills Stuart's men. In retaliation, Stuart impersonates air traffic control and fakes a British airplane's altimeter reading by recalibrating sea level. McClane is unable to warn off the airplane which crashes, killing everyone aboard. Esperanza's plane lands and McClane wounds Esperanza before Stuart and his men arrive. They blow up the plane and take Esperanza to the church. A Blue Light team arrives, led by Major Grant, of whom Stuart is a protégé. Grant's men and McClane attack the church. McClane kills one of Stuart's men and gives chase with his gun, but the mercenaries escape on snowmobiles. McClane follows but his vehicle is destroyed by gunfire. McClane realizes the gun was filled with blanks; the earlier firefight was staged and Grant's team is working with Stuart. Grant, Stuart, their men and Esperanza rendezvous at an airport hangar, where a Boeing 747 is waiting for them. On Holly's flight, reporter Richard Thornburg becomes suspicious as to why the plane has not landed. He taps into the cockpit communications and records a transmission from Barnes to all the circling airplanes describing the situation. From the airplane's lavatory, Richard broadcasts the recording, leading to a panic in the airport terminal which prevents McClane and Lorenzo from getting to the 747. Holly subdues Thornburg with a fellow passenger's taser. McClane asks reporter Samantha Coleman's crew to fly him via helicopter to intercept the 747. McClane jumps onto the wing and uses his coat to jam the aileron, preventing the plane from taking off. During a melee, McClane kicks Grant into a jet engine. While fighting Stuart, McClane opens a fuel valve in the engine pylon just as Stuart kicks him off the wing. McClane uses a cigarette lighter to ignite the fuel trail, causing the plane to explode and killing everyone on board. The fire trail serves as a landing guide for the circling aircraft to land safely. McClane and Holly are reunited. Marvin picks them up in his airport cart just as Lorenzo turns up asking if McClane got a parking ticket outside his airport. Lorenzo rips up the ticket and says "What the hell, it's Christmas!" Marvin drives McClane and Holly away.

The protagonist XXXX (otherwise unnamed) is a London cocaine distributor who abhors violence and operates with the care and professionalism of a legitimate businessman. His chief associates are his enforcer and partner Morty, and Gene, an Irish gangster who serves as his liaison to mob boss Jimmy Price. Just as XXXX is ready to retire from criminal life, he is summoned to a lunch meeting with Jimmy, who gives him two tasks. The first is to track down Charlie, the drug-addicted runaway daughter of one of Price's associates. XXXX enlists the con men Cody and Tiptoes to find her; they learn that Charlie has apparently been kidnapped, but are unable to discover who abducted her. The second task is for XXXX to oversee the purchase of one million ecstasy tablets from the "Duke", a low-level criminal who recently returned to London from Amsterdam with his girlfriend Slasher and crew of thugs led by his right-hand man Gazza. Unbeknownst to XXXX, the Duke and his crew have stolen the pills from a gang of Serbian war criminals. He meets the Duke's feckless nephew, Sidney, and finds himself attracted to his girlfriend Tammy. XXXX tries to broker the sale of the pills to Liverpool gangsters Trevor and Shanks but they refuse, informing him of their origin and that the vengeful Serbians have sent the assassin Dragan to recover the pills and kill the thieves. As the Duke had mentioned his name to the Serbians, XXXX is also a target. XXXX arranges a tryst with Tammy but is kidnapped and brought to Eddie Temple, a wealthy crime lord. Eddie explains that Charlie is his daughter, whom he has recovered; Jimmy, having recently lost a fortune due to bad investments he blames on Eddie, wanted her as a hostage until Eddie recouped his losses. Eddie gives XXXX a recording, revealing that Jimmy has been working as an informant for Scotland Yard, planning to betray XXXX to the police once the pills were sold in exchange for immunity for his own crimes and XXXX's money. Eddie demands that XXXX sell him the pills instead. XXXX assassinates Jimmy at his home, but later finds that his accountant, an associate of Jimmy's, has vanished along with XXXX's money. Confronted by Gene and Morty, he shares the evidence of Jimmy's betrayal, and the pair acknowledge him as the new acting boss. Gene shows them the corpse of the Duke, who was killed by one of his men when Slasher threatened to go to the police if Jimmy did not help them out of their situation. XXXX hires hitman Lucky, an associate of Trevor and Shanks, to ambush and kill Dragan, but Dragan kills Lucky first and makes XXXX promise to recover the pills. Sidney brings XXXX to Duke's old hideout, and, as he tries to bargain with Gazza for the pills, the police arrive. XXXX and the Duke's gang barely escape the raid, while Dragan watches from afar as the pills are confiscated. However, it turns out that XXXX arranged for the raid, with Cody and Tiptoes posing as officers to secure the pills. XXXX delivers the Duke's severed head to Dragan as a peace offering; satisfied, Dragan reports to the Serbians that the police have seized the drugs. The Serbians accept the loss, which is revealed to be a small amount in comparison to their overall manufacturing capacity. When XXXX and his crew arrive at Eddie's warehouse to sell the pills as arranged, Eddie's henchmen relieve them of the drugs at gunpoint, and Eddie welcomes him to the "layer cake" of criminal hierarchy. Having anticipated this double-cross, XXXX arranges Trevor and Shanks to gun down Eddie's men in an armed robbery, take the drugs, and sell them via Dizzy so he can settle his accounts. The gang assembles for lunch at the Stoke Park Country Club, honouring their new boss, but XXXX declines their offer of leadership and follows up on his initial plan to retire. With Tammy on his arm, he leaves the club, but is shot by a jilted yet apologetic Sidney. He collapses, bleeding out on the steps.

On the night that Miller's Comet passes Earth, eight friends gather for a dinner party at the home of couple Mike and Lee. Emily is hesitant to accompany her boyfriend Kevin on an extended business trip abroad. Amir has brought Kevin's ex-girlfriend Laurie, who flirts inappropriately with Kevin. A power outage occurs. Mike and Lee get out candles and colored glow sticks. The friends each take a blue glow stick and venture outside, where the neighborhood is dark except for one house that has lights. Back inside, they notice a broken glass no one remembers damaging. Amir and Hugh decide to ask to use the phone at the lit-up house, as Hugh's physicist brother had insisted Hugh call him if "anything strange" were to happen during the comet's passing and as no one's mobile phone has a signal. Hugh and Amir return. Hugh has a cut forehead and Amir has brought back a box he found at the other house containing a ping-pong paddle and photographs of everyone with numbers written on the backs. Hugh says he looked through the window of the other house and saw a table set for eight. They surmise the other house might be an alternate version of theirs. Hugh writes a note to leave at the other house, only to find an exact copy of the note pinned to their own door. Emily, Kevin, Mike, and Laurie decide to go to the other house. On the way, they encounter another group of four people who look like them, carrying red glow sticks rather than blue. Each group flees back to their houses. Hugh retrieves his brother's book from his car, which deals with quantum decoherence. They speculate that the comet has created mirror realities, one of which will collapse after the comet has passed. They surmise that anyone passing through a particularly dark area outside will emerge into a different reality. Mike drinks heavily and considers killing their doubles before the doubles can kill them. He decides to write a blackmail note to the other Mike to keep him from the book. The group realizes Hugh and Amir, in their midst, came from the other house. The two take the box and leave, then return carrying blue glow sticks. They had found two notes at the other house, showing that the split created more than just two alternate realities. Beth sees Laurie kissing Kevin in the hallway. Someone outside smashes Hugh's car window. Emily retrieves the ring Kevin gave her from her car. Talking to Kevin, Emily realizes she is from a different reality. The group creates their own box to validate they are all from the same reality. In addition to numbering the photographs by rolling dice, they include a randomly chosen object. Emily deduces that only Lee and Beth, who never left the house, originate from that house; she herself, Kevin, and Laurie are from a different house; Hugh and Amir are from a third house; and Mike is from a fourth. The blackmail note arrives under the door, revealing an adulterous liaison between Mike and Beth. Another Mike breaks in, attacks his double and leaves. Emily goes out and looks into several alternate houses until she finds one in which no one seems aware of the split. She lures everyone out of the house by smashing Hugh's car window, then ambushes the alternate Emily, sedating her with ketamine when she gets a ring out of her car and locking her in the trunk. She takes her other self's place while Miller's Comet breaks apart overhead, but must subdue and hide another Emily who crawls into the bathroom. She takes the ring from her defeated self after losing her own in the altercation, then returns to the living room, where she passes out. Emily wakes in daylight on the sofa with the rest of the party apparently none the wiser. Kevin returns her ring, which he found in the bathroom. His cell phone rings; bizarrely, Emily is calling. Emily looks at the two rings as Kevin answers the phone and then turns to look at her.