The film takes place in two different times: the present and 11 years earlier. The two plot lines are told in parallel through flashbacks. In 2002, software engineer Alan Russell moves into a new house with his wife Marie, 10-year-old son Tim, and 12-year-old daughter Kaylie. Alan purchases an antique mirror to decorate his office. Unbeknownst to them, the mirror supernaturally induces hallucinations. Marie is haunted by visions of her own body decaying, while Alan is seduced by a mysterious and ghostly woman named Marisol Chavez who has mirrors in place of eyes. In 2013, Tim is discharged from a psychiatric hospital, having been convinced that there were no supernatural events involved in his parents' deaths. Kaylie has spent most of her young adulthood researching the history and perceived powers of the mirror. Using her position as an employee of an auction house, she obtains access to the mirror and has it transported to the family home, where she places it in a room filled with surveillance cameras and a "kill switch" — an anchor attached to the ceiling on a pivot, positioned to swing down and smash the mirror. Kaylie intends to destroy the mirror, but first wants to document its power, proving both Alan's and Tim's innocence. Over time back in 2002, the parents become psychotic: Alan isolates himself in his office and Marie becomes withdrawn and paranoid. All of the plants in the house die, and their family dog Mason disappears after being shut in the office with the mirror. After Kaylie sees Alan with Marisol, she tells her mother and the parents fight. One night, Marie, distraught over her husband's supposed affair, tries to harm the mirror, finally becoming possessed by it, and attempts to kill her children, but Alan locks her away. When the family runs out of food, the children realize that their father is now permanently under the influence of the mirror too, so Kaylie goes to seek help from their mother and finds her chained to the wall, acting like an animal. Kaylie and Tim try going to their neighbors for help, but the neighbors disbelieve their stories. When Kaylie attempts to use the phone, she discovers that all of her phone calls are answered by the same man. The fully possessed Alan eventually loads up a gun previously purchased by him and unchains Marie, with both parents attacking the children. Marie briefly comes to her senses, only to be shot dead by Alan. The children try to destroy the mirror but it tricks them, making them believe they are hitting the mirror when they are actually hitting the wall. Alan also experiences a moment of lucidity and kills himself by forcing Tim to pull the trigger of the gun and shoot him, causing a small crack in the corner of the mirror in the process. Before dying, he begs the children to run, but Marisol and other victims of the mirror appear as ghosts. The police arrive and take Tim into custody. Before the siblings are separated, they promise to never forget what happened with the mirror, one day reunite as adults and destroy it. As Tim is taken away and put behind bars, he sees the ghosts of his parents watching him from the house. Back in 2013, Tim attempts to convince Kaylie that she is wrong and the siblings argue. When they notice the houseplants begin to wilt, they review the camera footage and see themselves performing actions they do not remember doing. Tim finally accepts the mirror's supernatural power and attempts to escape the house with Kaylie, only for the pair to be drawn back by the mirror's influence. Seeing a hallucination of her mother, Kaylie stabs it in the neck, only to realize that she has stabbed Michael Dumont, her fiancé and one of her fail-safes, who has come to check on her. They try to call the police, but are only able to reach the same voice who spoke to them on the phone as children. At this point, they see their doppelgangers inside the house standing in front of the mirror. Realizing that the 9-1-1 call is not going through, they go back inside the house. Kaylie and Tim begin hallucinating by seeing younger versions of themselves, the past and the present merging into each other. They are separated and each of them relives the nightmare from their youth. Tim awakens alone in the room with the mirror, while simultaneously a younger Kaylie hallucinates her mother beckoning her from the mirror. Tim releases the anchor, unable to see that Kaylie is standing before the mirror, and inadvertently kills her instead of destroying it. The police arrive and arrest Tim, who is hysterical, just as they did when he was younger. As both a boy and an adult, Tim claims the mirror is responsible. As he is taken away, Tim's adult incarnation sees Kaylie's ghost standing in the house with his parents.

London-based journalist Martin Sixsmith has lost his job as a government adviser. He is approached at a party by the daughter of Philomena Lee. She suggests that he write a story about her mother, who was forced to give up her toddler son Anthony nearly fifty years ago. Though Sixsmith is initially reluctant to write a human interest story, he meets Philomena and decides to investigate her case. In 1951, Philomena became pregnant after having sex with a man she did not know at a county fair, so was sent by her father to Sean Ross Abbey in Roscrea in Ireland. After giving birth, she was forced to work in the convent laundry for four years, with little contact with her son. The nuns gave her son up for adoption without giving Philomena a chance to say goodbye. She kept her lost son a secret from her family for nearly fifty years. Martin and Philomena begin their search at the convent. The nuns claim that the adoption records were destroyed in a fire years earlier; they did not, however, lose the contract she was forced to sign decades ago forbidding her from contacting her son, which Martin considers suspicious. At a pub, the locals tell Martin that the convent burnt the records deliberately, and that most of the children were sold for £1,000 each to wealthy Americans. Martin's investigation reaches a dead end in Ireland, but he receives a promising lead from the United States so invites Philomena to accompany him there. His contacts help him discover that Anthony was renamed Michael A. Hess, who became a lawyer and senior official in the Reagan and George H. W. Bush administrations. When Philomena notices Martin in the background of a photo of Michael, he remembers that he met him years earlier while working in the US. They also learn that he has been dead for eight years. Philomena decides she wants to meet people who knew Michael to learn more about him from them. Visiting a former colleague of Michael's they discover that Michael was gay and died of AIDS. They also visit his 'sister' Mary, who was adopted at the same time from the convent, and learn that they were both emotionally and physically abused by their adoptive parents, and hear about Michael’s partner, Pete Olsson. After avoiding Martin's attempts to contact him, Pete agrees to talk to Philomena. He shows her some videos of his life with Michael. To Martin and Philomena's surprise, they see footage of Michael, dated shortly before he died, at the Abbey where he was adopted, and Pete explains that, although he never told his family, Michael had privately wondered about his birth mother all his life, so had returned to Ireland in his final months to try to find her. Pete informs them that the nuns had told Michael that his mother had abandoned him and they had lost contact with her. He also reveals that, against his parents' wishes, he had Michael buried in the convent's cemetery. Philomena and Martin return to the convent to ask where Michael's grave is. Despite Philomena's pleas, Martin angrily forces his way into the private quarters and argues with an elderly nun, Sister Hildegarde McNulty, who worked at the convent when Anthony was forcibly adopted. He accuses her of lying to Anthony and denying him the chance to finally reunite with Philomena, purely out of self-righteousness. Hildegarde is unrepentant, saying that losing her son was Philomena's penance for having sex out of wedlock. Martin demands an apology, telling her that what she did was un-Christian, but is speechless when Philomena instead chooses to forgive her of her own volition. She then asks to see her son's grave, where Martin tells her he has chosen not to publish the story. Philomena tells him to publish it anyway.

Hirayama works as a public toilet cleaner for The Tokyo Toilet project in Tokyo 's upscale Shibuya district, across town from his modest home in a middle-class neighbourhood east of the Sumida River. He repeats his structured, repetitive routine each day, starting at dawn. His pride in his work is apparent by its thoroughness and precision. He dedicates his free time to his passion for music cassettes, which he listens to in his van to and from work, and to his books (Faulkner, Kōda, Highsmith), which he reads every night before going to sleep. His dreams are shown in flickery impressionistic black-and-white sequences at the end of every day. Hirayama is also fond of trees and spends time gardening and photographing trees. He eats a sandwich every day in the shade under trees in the grounds of a shrine, and takes film photos of their branches and leaves and the 'Komorebi' (木漏れ日) – sunlight filtered by the leaves. Hirayama's love of trees is contrasted with the repeated appearance of the Tokyo Skytree during his drives and bike rides through the city. Hirayama's young assistant, Takashi, is often late, loud, and not as thorough. One day, a young woman named Aya calls on Takashi at the toilet he is cleaning, so he hurries to finish. He tries to leave with Aya, but his motorbike will not start, so he persuades Hirayama to let him use his van. When Aya says Takashi can stay with her as she works at a girls bar, he complains that he is broke. Unbeknownst to Hirayama, Takashi slips Hirayama's Patti Smith tape into Aya's purse. Takashi talks Hirayama into going into a shop to get some of his cassettes appraised. When Takashi discovers they are valuable, he urges Hirayama to sell but Hirayama refuses, giving him some cash so he can take Aya out. When Hirayama runs out of fuel, he is forced to sell a cassette for fuel money. Hirayama commences a tic-tac-toe game with a stranger after finding a piece of paper left hidden in a stall. The game continues over the course of the film. He exchanges furtive glances with a woman eating lunch one bench over. Aya catches up with Hirayama to return his cassette. She asks to play it in his van one last time, and then gives him a thank-you kiss on the cheek, leaving him visibly startled. On his free day, Hirayama does his laundry, takes the film with his tree photos to be developed, cleans his flat, buys a new book, and dines at a restaurant where the proprietor shares gossip with him. Niko, Hirayama's niece, shows up unannounced, having run away from his wealthy estranged sister Keiko's home. Hirayama lets Niko accompany him to work during the next two days. They photograph the trees in the park and ride bikes together. Eventually, Keiko comes to pick up Niko in a chauffeured car. Keiko tells him that their father's dementia has worsened and asks whether Hirayama will visit him in the nursing home where he lives. She says that he does not recognise anything anymore and will not behave the way he did before. Hirayama sorrowfully refuses but hugs his sister goodbye. Before she leaves, she asks him whether he really cleans toilets for a living, and he says yes. As they drive away, Hirayama begins to cry inconsolably. The next day, Takashi quits without giving notice, leaving Hirayama to cover his shift. Later, as Hirayama goes to his usual restaurant, he sees the female proprietor embracing a man. Hirayama hurries off, buying cigarettes and three bottled highballs to consume at a nearby riverbank. The man Hirayama saw at the restaurant approaches and asks him for a cigarette. The man tells him the restaurant proprietor is his ex-wife whom he had not seen in seven years, and that she opened her restaurant the year after divorcing him. He says he visited her to make peace before he dies of cancer, telling Hirayama to look after her. Hirayama lightens the mood by offering him a drink and inviting him to play shadow tag, and they eventually part ways. The following morning, Hirayama begins another workweek. As he drives his van and listens to Nina Simone sing " Feeling Good ", a range of powerful emotions wash over his face.

In 2018, Programmer Pan Sheng is lured overseas by a supposed high-paying job and is trafficked into a Canaan slave-camp-like fraud factory, where he is threatened by violence into committing online fraud on behalf of the controlling syndicate. In the camp, Sheng encounters model Liang Anna, who was similarly recruited under false pretenses, and who works on-camera as a dealer in the online gambling section. Sheng offers to help Anna reach her sales target, after which she will supposedly be allowed to leave and can send a message on Sheng's behalf to his loved ones. Sheng uses Anna's identity to catfish Gu Tianzhi, a young man who becomes addicted to online gambling. Sheng baits Tianzhi with "tips" to encourage increased betting, which pulls Tianzhi into debt. Tianzhi's girlfriend Song Yu goes to the police, and is told by officer Zhao Dongran that Tianzhi is likely the victim of a scam. During the 2018 FIFA World Cup final, Tianzhi sits at a bar and bets a large amount of money on the winning team, and is euphoric watching the game's end on television, thinking he has made a fortune. Instead, he finds Yu has cancelled the bet at the last minute. Tianzhi obtains more money from his grandmother, who has dementia, and is tricked into performing a direct transfer of ¥ 8 million to "Anna", which is detected by but cannot be stopped by Zhao's online monitoring taskforce. The money is quickly withdrawn by the syndicate, who celebrate the success while Tianzhi tries to commit suicide by falling out his apartment window. Anna is told by the camp's manager Lu Bingkun that her sales target has increased and she cannot leave. Sheng offers to build an app for Lu to run scams efficiently, and is given new privileges for his efforts. Sheng writes "SOS", "12308 " on a bank note seeking rescue, but it is intercepted, and Sheng and Anna, voluntarily admit, are both tortured as punishment. While being transferred in a bus, Anna jumps out and runs to a police station, but the officers work for the syndicate. Cai, Lu's enforcer, stages Anna's murder but lets her escape. Zhao meets Song Yu again, and is able to connect the messages on Tianzhi's phone with Anna's real identity. Anna manages to return home, where she is picked up by the police but refuses to explain where she's been. Anna is made to attend a scam awareness seminar and is taken to see Tianzhi in the hospital in a vegetative state. This compels her to share what she knows about the syndicate. A large-scale anti-fraud operation is launched. Lu and Cai become persons of interest and multiple raids are carried out. When Zhao and the officers investigate the camp, they find it empty and the computers removed. The taskforce is about to leave the country when they receive a call from Sheng's friend who has just realized that Sheng has been sending coded messages to him asking for help. Using those messages, Zhao and the taskforce are able to locate the syndicate's hiding place in an elementary school, which they successfully raid and arrest everyone except Cai, who is killed in a shootout. Although Lu has all the computers destroyed, the app Sheng built for Lu's phone retains information of the scams and victims, which is used as evidence against the syndicate. In an epilogue, Zhao leads an anti-fraud conference with Song Yu, Sheng and Anna as speakers. In the audience, a member of the syndicate watches them.

"Ghetto" Pat Calhoun and Perfidia Beverly Hills are lovers and members of a far-left militant revolutionary group, the French 75. While breaking out detained immigrants from Otay Mesa Detention Center, Perfidia sexually humiliates the commanding officer, Steven J. Lockjaw, who becomes obsessed with her sexually. Later, when Lockjaw catches Perfidia planting a bomb, he lets her go after she agrees to his demand to meet him for sex. Soon after, Perfidia becomes pregnant. After Perfidia gives birth to a girl named Charlene, Pat tries to persuade her to settle down, but she instead abandons Pat and Charlene to continue her revolutionary activities. Perfidia is arrested after murdering a security guard during a botched bank robbery. Lockjaw arranges for her to avoid prison in exchange for information on key French 75 members. Perfidia enters witness protection, while Lockjaw uses the information she provided to hunt down and summarily execute her comrades. French 75 member Howard Sommerville gives Pat and Charlene stolen identities as Bob and Willa Ferguson, while Perfidia flees witness protection for Mexico. Sixteen years later, living off-the-grid in the sanctuary city of Baktan Cross, California, Bob has become a paranoid stoner. He is protective of Willa, now a free-spirited and self-reliant teenager who resents Bob's substance abuse, and told her that her mother was a hero who died when she was a baby. Through his anti-immigration efforts, Lockjaw has become a colonel and a prominent figure within the U.S. security agencies. When Lockjaw is invited to become a member of the Christmas Adventurers Club, a white supremacist secret society, he seeks to kill Willa to hide his past interracial relationship with Perfidia. He hires bounty hunter Avanti Q to capture Howard, whose distress signal goes out to the remaining members of the French 75. Using an immigration and drug enforcement operation as cover, Lockjaw sends troops to Baktan Cross. French 75 member Deandra rescues Willa before her school dance is raided and takes her to a convent of revolutionary nuns, where she guesses the truth about her mother's betrayal. While high at home, Bob is warned by the French 75 about Lockjaw, whose men then raid his house. Escaping through a tunnel, Bob is helped by Sergio St. Carlos, Willa's karate sensei and a community leader, who also evacuates immigrants via a hidden passage. After learning about the convent from another French 75 member, Bob flees with Sergio's students across rooftops but falls and is arrested, although not recognized. The Christmas Adventurers find evidence of Lockjaw's relationship with Perfidia, including the possibility that he had a child with her, and send member Tim Smith to kill him and Willa. By tracing her phone, Lockjaw locates Willa at the convent, where Deandra is arrested. Holding Willa hostage, Lockjaw tests their DNA in front of her, confirming she is his biological daughter. Sergio arranges Bob's escape and drives him to the convent, throwing him out of the car when police begin to pursue them. Bob steals a car and reaches the convent, unsuccessfully attempting to kill Lockjaw with Sergio's rifle. Lockjaw hires Avanti to kill Willa, but after refusing over her age, Avanti agrees instead to deliver her to a far-right militia. Tim tracks down Lockjaw while driving and shoots him in the face. While searching for Willa, Bob discovers Lockjaw's body and crash site. Avanti brings Willa to the militia, but after a change of heart, frees her and is killed in a shootout with the militia. Willa escapes with Avanti's car and pistol, only for Tim to begin tailing her as Bob tries to catch up. Willa lures Tim into a crash by exploiting a blind summit, shooting and killing him when he fails to recite the revolutionary countersign. Bob finds Willa and they embrace. Some time later, a severely scarred Lockjaw is seemingly welcomed into the Christmas Adventurers Club, but is fatally gassed and cremated shortly afterward. Returning home with Willa, Bob gives her a letter from Perfidia, in which she apologizes for her actions and vows to someday reunite with her family. Later, Bob gives Willa his blessing as she departs for a protest in Oakland.

Fire and Rescue Crew 7 of Prescott, Arizona, superintended by Eric Marsh, responds to the Cave Creek wildfire. Eric predicts that the fire will threaten a residential area, but is disregarded by the assigned superintendent. Eric's fear comes true; he vents his frustration to fire chief and close friend Duane Steinbrink, warning that when a wildfire threatens Prescott, his crew will not be allowed to fight it directly as they lack Hotshot certification. Eric asks for Duane's help, who successfully vouches for the crew with the mayor of Prescott. Crew 7 has until the end of the fire season to pass the evaluation. Meanwhile, 21-year-old heroin addict Brendan McDonough learns that his ex-girlfriend Natalie is pregnant and does not want him involved with the child. Brendan is arrested for larceny, which prompts his mother to evict him from her house. Determined to provide support for his newborn daughter, Brendan interviews with Eric, who gives him an opportunity. After months of training, the crew are given an evaluation during a wildfire deployment as they were set to battle the Horseshoe 2 Fire in the Chiricahuas near the town of Portal. Eric commands his crew but is criticized by their evaluator, Hayes, who Eric bluntly disregards. The fire is halted by Eric's strategy and the crew are certified, officially becoming the first municipal hotshot crew in history, the Granite Mountain Hotshots. Throughout the season, the Granite Mountain crew are deployed across the country. Brendan, who's been anonymously dropping off baby supplies at Natalie's doorstep, is finally accepted by Natalie and allowed to see his daughter. Near Prescott, the crew saves a landmark Alligator juniper and are hailed as local heroes. After battling the fire, Brendan is bitten by a rattlesnake and is rushed to the hospital. Brendan expresses his concerns to Eric about being there for his daughter and asks if he would recommend him for a structural firefighting position next season. Eric snaps, stating that nobody would hire him due to his prior drug addiction. On the way home, Eric has an argument with his wife Amanda, who challenges him about this; reminding him about his own previous drug/alcohol addiction (from which he has been clean for a number of years and which lead to him meeting Amanda) The two talk about starting a family, which they had previously decided not to do due to the nature of their past. Amanda makes it clear to Eric that it is now something she would like to revisit. Eric stops the truck and leaves Amanda alone; unwilling to continue the conversation he leaves stating that he is going for a walk. He ends up at Duane’s house where he speaks openly about his fears. After speaking with Duane, Eric returns to Amanda, announcing that he is ready to settle down. The Granite Mountain Hotshots are called to the Yarnell Hill Fire. Eric informs his captain, Jesse Steed, that he will step down as superintendent after this season and offers Jesse his job. Eric also apologizes to Brendan and promises that he will help him with the transfer. The crew assembles a controlled burn, but is doused mistakenly by an airtanker. Marsh sends Brendan, still recovering from the snakebite, as the lookout, while the remaining crew move to find another suitable location. The wind suddenly shifts, and the fire jumps a trigger point. Brendan is rescued by another hotshot crew while the others relocate to a safe zone, but the fire's speed and intensity continues to increase. The wind picks up again, jumping Granite Mountain's safe zone; cutting them off from escape. Clearing a small site quickly, Eric attempts to douse the blaze with an overhead airtanker, but it misses the drop zone. The crew deploys under their fire shelters as the fire sweeps over them. Brendan listens into the radio traffic, and is devastated when a call finally comes in from the first responders who arrive at their shelters; all 19 of his crewmates have perished. Though the information is treated sensitively, rumors flare amongst the devastated families of what has happened. Brendan, being the sole survivor, demands to meet with them at the gather point at Prescott Middle School. Upon arriving, the families' worst fears are confirmed, with Brendan suffering a psychological breakdown due to survivors guilt. He is ultimately consoled by a grieving newly widowed Amanda. Three years later, Amanda goes on a horseback ride with the horse she rescued earlier in the film watching over a series of horses from a nearby ridge. Brendan takes his daughter to the juniper tree Granite Mountain saved, now adorned as a memorial to the hotshots. The end credits dedicate the film to the 19 fallen firefighters, displaying photos of the real hotshots alongside the actors who played them in the film, and notes that the Yarnell Hill Fire remains the largest loss of firefighter life in a single day since the September 11 attacks.

In early 2003, GCHQ analyst Katharine Gun obtains a memo detailing a joint United States and British operation to spy on diplomats from several non – permanent United Nations Security Council member states (Cameroon, Chile, Bulgaria and Guinea), to "dig dirt" on them. This was to influence the Security Council into passing a resolution supporting an invasion of Iraq. Angered that the UK is being led into a war on false pretences, Katharine leaks the memo to a friend involved in the anti-war movement, who passes it to anti-war activist Yvonne Ridley. She gets it to The Observer journalist Martin Bright. The Observer foreign editor Peter Beaumont allows Martin to investigate the story. To verify the memo's authenticity, Martin enlists the help of the Observer ' s Washington correspondent Ed Vulliamy to contact the memo's author Frank Koza, Chief of Staff at the "regional targets" section of the NSA. Despite the Observer ' s pro-war stance, Peter convinces the chief editor Roger Alton that the leaked memo is worth publishing. The leaked memo's publication in March 2003 generates public and media interest. The Drudge Report attempts to discredit the document as a fake, as staffer Nicole Mowbray had inadvertently changed the text from American to British English with a spellchecker. However, Martin is able to produce the original memo, confirming its authenticity. Katharine's actions prompt GCHQ to launch an internal investigation. Seeking to prevent an invasion of Iraq and to protect her colleagues from suspicion, Katharine confesses to the leak. She is arrested, questioned, then released on bail. Following the outbreak of the Iraq War, Katharine seeks the services of the Liberty lawyers Ben Emmerson and Shami Chakrabarti. The British Government decides to charge her with violating the Official Secrets Act, tasking the Director of Public Prosecutions, Ken Macdonald, with the prosecution. To exert pressure, the British authorities attempt to deport her husband Yasar Gun, a Turkish Kurd. However, Katharine is able to halt the deportation with the help of her MP, Nigel Jones. Katharine's defence strategy is that she acted from loyalty to her country, seeking to prevent it from being led into an unlawful war. With the help of Martin, Ed, and former Foreign Office deputy legal adviser Elizabeth Wilmshurst, Ben discovers that the Attorney General Peter Goldsmith changed his position on the legality of the war after meeting lawyers from the Bush Administration. Despite the odds against her, Katharine refuses to plead guilty in exchange for a reduced charge. In court, the Crown prosecutor offers no evidence against Katharine. Ben responds that this is because doing so would have shown that the Blair government led the UK into war on false pretences. The film then mentions the human toll of the Iraq War and that Lord Goldsmith's advice on the illegality of the Iraq War was made public in 2010. It ends with footage of the real Katharine addressing the media following the dismissal of her case, and Ben shunning Ken for putting Katharine through the ordeal "to make an example of her".

Kang Jae-hyeok works at the aging Hanbyul Nuclear Power Plant, which is their namesake town's only source of energy and jobs. Jae-hyeok, who had earlier lost both his father and brother working at the plant in his early years, lives with his mother, sister-in-law, and nephew Min-jae. He expresses his desire to work at a fishing vessel to make money for his family rather than work at the plant, but is discouraged by everyone he knows, including his childhood friend & fiancée Yeon-joo. Pyeong-seok is one of the head operators of the plant, who alongside a coalition of his concerned plant workers and anti-nuclear activists, tries to get the President of South Korea Seok-ko Hang, to shut down the plant due to urgent safety concerns, but they are dismissed by the other senior plant operators, especially the Prime Minister. An earthquake suddenly strikes the town, causing the nuclear reactor to overheat. Due to the plant's aging safety systems, attempts to cool down the overheating reactor are ineffective. Meanwhile, Hang's administration fiercely debates between allowing the reactor to vent radioactive particles into the air to relieve pressure from the core or evacuating large population centers around the plant, before they settle on evacuating residents closest to the reactor. Due to the lack of a contingency plan in place, the only route leading out of town quickly became gridlocked. This critical delay led to the reactor building exploding before the crew could open the pressure release valves themselves, killing or injuring most of the plant workers. Jae-hyeok hauls out his friend Gil-seop and much of the workers out from the plant before he collapses from radiation poisoning. The KCDC quarantines the town's residents not far from the reactor. However. after Yeon-joo gets proof that the reactor exploded and delivers the news, they set up a jammer and locks the evacuees inside the evacuation center as they leave them for dead, except for the junior nurse Mi-sook, who is treating Jae-hyeok and other plant workers. Yeon-joo, along with the town's residents manage to break out from the evacuation center and commandeers one of the buses for their citizens to escape. Despite the firefighters' efforts to cool the reactors, some of the firefighting crew also began experiencing radiation poisoning symptoms as well. Hang, after fallen into depression for the reactor explosion, orders the firefighters to use seawater to decommission the reactors completely. He and Pyeong-seok discovers that there is a growing crack underneath the storage tank in the basement, putting the spent fuel rods in danger of overheating. When the Army 's military engineers refuse to step in, Hang addresses to the nation, requesting aid from the plant workers to perform a dangerous operation of sealing the cracks in the basement. Jae-hyeok bitterly declines, but at the insistence of Gil-seop, he eventually agrees for the sake of the people. He calls a distraught Yeon-joo before he boards on a bus back to the town along with their surviving crew. During their operation, the crack underneath the coolant tank grew bigger and they are ordered to retreat. Jae-hyeok suggests they seal the door and blow up the tank to allow the spent fuel rods to fall into the basement, effectively creating a new tank. However, at the current situation, both of these steps must be executed simultaneously, meaning one will not be leaving out alive. Jae-hyeok, the only person among the group who can operate explosives and having already been too sick from radiation poisoning, volunteers to sacrifice himself, allowing the workers to then seal himself into the waste room before fleeing the area. Jae-hyeok uses his helmet-mounted camera to broadcast a farewell message to his family and Yeon-joo before blowing himself up, sending all the fuel rods into the flooded basement and averting a larger nuclear disaster.

Setsuko Kawashima is a lonely, middle-aged office worker in Tokyo who is aloof from her co-workers, lives in a cluttered studio apartment and is estranged from her sister, Ayako. One day, she meets with her niece Mika, who tells Setsuko that she signed up for a year of English classes but can no longer afford to attend, as she needs to save money and keep working. Mika persuades Setsuko to buy her out and sends her to the school for a free first class. At the school, Setsuko meets John, an American teacher who hugs her warmly, gives her the American name of Lucy and a bright blonde wig so she can adopt an American persona. She meets Takeshi Komori, a classmate in the English class who goes by the name Tom. Setsuko is quickly charmed by John and decides to continue attending classes. At their next session, she learns that John has abruptly quit to return to the United States. Outside the school, she spots John and Mika kissing and getting into a cab. Ayako informs her that Mika has moved to the US. Setsuko returns to English class, but finds the new teacher too conventional and leaves the school. When she receives a postcard from Mika containing her address in Los Angeles, Setsuko impulsively decides to follow her, with Ayako insisting on joining her, despite her strained relationship with her daughter Mika. It is revealed that Setsuko harbors resentment towards Ayako for stealing and marrying her boyfriend. Arriving in Los Angeles, the two are surprised to find only John at home, who claims that Mika has left him and he has no idea where she is. After raiding his room, however, Ayako discovers a postcard sent by Mika from a motel in San Diego. The sisters have John rent a car and drive them to the motel where Mika was last heard from. While waiting for Mika to reappear, John offers to teach Setsuko how to drive and the two end up having sex. Later that night, Setsuko goes to a tattoo parlor to get the same tattoo as John, but when she shows it to him, he rebuffs her. The next morning, Ayako confronts John and tells him to take her to Mika. He goes to his house where he introduces Ayako to his estranged wife and daughter, who know where Mika is but will not tell him. Setsuko, left alone at the motel, runs into Mika who tells her that she broke up with John after discovering his family. They have a picnic near the beach where Mika teases Setsuko about having a crush on John, and Setsuko responds by revealing that she had sex with John. The two women engage in a physical altercation, culminating in Mika jumping off a cliff in a suicide attempt, but she survives. At the hospital, an enraged John asks Setsuko if she told Mika about them. She insists that she loves John, but he rejects her and drives off. Ayako tells her to stay out of their lives. Back in Tokyo, Setsuko learns she is being transferred to another department, prompting her to quit. Shortly after leaving the office, she overhears her co-workers laughing and cheering. Distraught over losing John, her job, and her family, she attempts suicide by overdosing on pills at home. She is found by Takeshi, who makes her vomit the pills. She tries to seduce him, but he kindly rejects her advances. As they head to a subway station, Takeshi reveals that his son killed himself and that he blames himself for being too strict, which is why he enjoys slipping into his Tom persona. He asks Setsuko for a hug, and she agrees.

Kim Ki-taek and Chung-sook live in a semi-basement flat (banjiha) in Seoul with their daughter Ki-jung and son Ki-woo. As the family has financial struggles and low-income jobs, family friend Min-hyuk gives them a scholar's rock meant to promise wealth. Leaving to study abroad, he suggests that Ki-woo lie about his qualifications to take over Min-hyuk's job as an English tutor for Da-hye, the daughter of the wealthy but naïve Park family. Min-hyuk trusts Ki-woo because he likes Da-hye and wants to ask her out when he returns. After Ki-jung helps forge a certificate for him, Ki-woo, posing as a Yonsei University student named "Kevin", goes to the Parks' home, where he is hired by the mother Mrs Park by the end of his first lesson. The Kims' scheme is to secure jobs for each family member within the Park household while concealing their true identities. Ki-woo recommends "Jessica," actually Ki-jung, as an art therapist for the Parks' young son, Da-song, who has been traumatised after seeing a "ghost" in their kitchen. Ki-jung then frames Yoon, the Parks' chauffeur, by making it appear as though he had a sexual encounter in the car, leading to Ki-taek being hired as his replacement. The Kims exploit the peach allergy of the Parks' longtime housekeeper, Moon-gwang, to convince Mrs Park that Moon-gwang has tuberculosis, and Chung-sook is hired as her replacement. Meanwhile, Ki-woo begins a secret romantic relationship with Da-hye. While the Parks are away on a camping trip, the Kims revel in the luxuries of the house when Moon-gwang suddenly appears at the door, claiming to have forgotten something in the basement. She goes through a hidden entrance to an underground bunker created by the house's architect and previous owner, who had kept its existence secret from the Parks. There, Moon-gwang's husband, Geun-sae, has been hiding from loan sharks and is revealed to be the "ghost" Da-song saw. Moon-gwang begs Chung-sook to allow Geun-sae to continue living there in exchange for regular payments, but the three other Kims, who are eavesdropping, accidentally reveal their true identities. Moon-gwang films them and threatens to expose their deception to the Parks. After the Parks call to inform the Kims that they are returning early due to a sudden severe rainstorm, the Kims quickly destroy all evidence of their ruse and subdue Moon-gwang and Geun-sae in the bunker, although Moon-gwang is injured during the struggle. The Kims manage to escape, but the torrential rain floods their flat with sewage water, forcing them to take shelter in a gymnasium alongside other displaced people. The next day, Mrs Park organises an impromptu garden party for Da-song's birthday, with the elder Kims assisting while the younger Kims are invited as guests. Ki-woo enters the bunker with his scholar's rock, with intentions unknown. Moon-gwang is already dead from injuries sustained in the previous day's brawl; Geun-sae bludgeons Ki-woo with the rock, leaving him unconscious. Geun-sae then leaves the bunker and stabs Ki-jung with a kitchen knife in front of horrified party guests. Da-song faints upon seeing the "ghost" again. Chung-sook impales Geun-sae with a barbecue skewer after a struggle. While Ki-taek tends to Ki-jung, Mr Park orders him to drive Da-song to the hospital. Ki-taek, gradually enraged by the Parks' lack of empathy or awareness of their own privilege, stabs him with Geun-sae's knife and flees. Weeks later, Ki-woo is recovering from brain surgery, and he and Chung-sook have been convicted of fraud and placed on probation. Ki-jung has died from her injuries, and Ki-taek – now a wanted fugitive – has disappeared. Geun-sae is presumed to have been a random homeless man, and the motives for the murders remain unsolved. Ki-woo spies on the Parks' former home, now owned by a foreign family, and notices a Morse code message in a light visible from outside. Ki-taek, hiding in the bunker, has buried Moon-gwang in the garden and sends daily messages, hoping Ki-woo will see them. Still living in a semi-basement flat with his mother, Ki-woo writes a letter to Ki-taek, vowing to earn enough money one day to buy the house and free him.

In the first section of the film, the cast and crew of a low-budget zombie film called True Fear are shooting at an abandoned water filtration plant. Director Higurashi, desperate for film success due to mounting debts and frustrated at the actors' work, arranges for a blood pentagram to be painted to revive real zombies per the plant's haunted past. The cameraman turns into a zombie and bites assistant director Kasahara, turning him into one as well. Actress Chinatsu, actor Ko, and makeup artist Nao lock the zombies out of the plant. Higurashi insists they continue filming using the real zombies. The sound engineer rushes out of the plant and is infected. Higurashi brings the zombified sound engineer back in for more footage, throwing him at the actors. Nao decapitates the zombified sound engineer and is splattered with zombie blood. Chinatsu, Ko, and Nao attempt to escape, but Higurashi facilitates an attack by zombified Kasahara while he films. Chinatsu is confronted by the zombies and saved by Ko. They reunite with Nao, who suspects that Chinatsu is infected. Nao attempts to kill Chinatsu and chases her, dispatching the zombies in the process. Chinatsu escapes to a roof, with Nao and Ko following. Offscreen, Ko kills Nao with an axe to save Chinatsu. Chinatsu thinks she is infected and runs away to a building with a pentagram painted on the outside wall. An unidentified zombie approaches Chinatsu and leaves. Chinatsu also exits the building, finding an axe before seeing Ko wandering on the roof. She approaches Ko to find that he has been zombified. Chinatsu confronts zombified Ko in a scene similar to the start of the film, and after being briefly interrupted by a mysteriously revived Nao, Chinatsu decapitates zombified Ko. Higurashi berates Chinatsu for going off script. Chinatsu kills Higurashi, and she ends the first section by standing on the blood pentagram in a trance-like state. The second section of the film is a flashback involving the personal lives of the fictional cast and crew of a production called One Cut of the Dead, a film-within-the-film of the same title (thus making True Fear a film-within-the-film within another film-within-the-film). Takayuki Higurashi, director of a TV drama starring alcoholic actor Manabu Hosoda, is approached by network executives to direct a low-budget zombie film in one take to launch the new Zombie Channel. He is initially reluctant, but accepts in hopes of reconnecting with his daughter Mao, a horror movie fanatic. Actors cast for One Cut of the Dead include idol Aika Matsumoto as Chinatsu, cynical actor Kazuaki Kamiya as Ko, Shunsuke Yamagoe as the sound engineer, and Hosoda as the cameraman. The One Cut of the Dead movie-within-the-movie is also revealed to be a live show, so no reshoots or delays are possible. The third section of the film depicts the chaotic shooting of One Cut of the Dead from behind the scenes. The actors cast as director and makeup artist could not make filming, forcing Takayuki and his wife Harumi to step in to fill their respective roles. During the shooting, Takayuki overacts his first scene by physically accosting Matsumoto. Hosoda passes out drunk and later vomits. Yamagoe's diarrhea leads to his character leaving the plant off-script. Dealing with these forces Takayuki and the other actors to start to improvise and make small talk. The main cameraman suffers a back injury and has to be replaced. Harumi goes off-script and attacks various real cast and crew during the scene of Nao chasing Chinatsu, forcing Takayuki to choke her out and later forcibly remove her from interrupting the ending scene between Chinatsu and Ko after she abruptly wakes up. The zombie who did not attack Chinatsu turns out to be a crew member giving instructions. The camera crane accidentally gets broken, forcing the real cast and crew to form a human pyramid in order to mimic a crane shot for the final shot, with Mao having to hold the camera standing atop Takayuki's shoulders. The faux-crane shot is successful, and the real cast and crew are elated at the successful filming. The final credits are shown over footage of the real-life filming by the One Cut of the Dead crew, including the faux-crane shot being taken from the top of a stepladder.

On November 9, in Palm Springs, Nyles wakes up and fails to consummate sex with his girlfriend Misty. That evening, Nyles attends a wedding reception for Tala and Abe. There, he bonds with the maid of honor, Tala's depressed half-sister Sarah. Nyles and Sarah leave the party to have sex in the nearby desert. As he undresses, Nyles is hit by an arrow shot by an assailant, then he crawls into a cave, warning Sarah not to follow him. Concerned for Nyles, she follows him and is sucked into a vortex. Sarah wakes up and realizes that it is November 9 again. She confronts Nyles, and he explains that by following him into the cave, Sarah has become stuck in a time loop with him; falling asleep or dying resets the loop, repeating November 9. Nyles reveals that the man who shot him, Roy, is from the wedding and that Nyles inadvertently trapped him in the time loop. For revenge, Roy sometimes hunts down Nyles, as he enjoys putting him through pain even though his "deaths" are only temporary. Sarah tries various methods to escape the loop, but is unsuccessful. Nyles, having already been in the loop for a long time, has become complacent and carefree, abandoning hope of escape. Sarah resigns herself to her fate and adopts Nyles' carefree and reckless lifestyle. Nyles and Sarah become close. They begin to look forward to their days together, where they are free to do anything without consequence. One night, Nyles and Sarah camp out in the desert, get high, and have sex. The day after, Sarah sleeps in and is woken up by Abe, with whom she had sex on November 8, the night before the wedding. Guilt-ridden, Sarah refuses to talk to Nyles about their previous night, expressing nihilism about their life in the loop. After being pulled over by Roy disguised as a cop, Sarah runs him over. She and Nyles argue, leading him to admit that he had sex with Sarah many times in the loop, something he previously lied about. An angry Sarah starts avoiding Nyles. Nyles feels lost without Sarah and spends days aimlessly moping, discovering Abe and Sarah's affair in the process. One day, Nyles visits Roy at his home in Irvine. Having now experienced a painful injury at the hands of Sarah, Roy realizes what he has put Nyles through, and they reconcile. Meanwhile, Sarah spends her days studying to become an expert in quantum physics and general relativity. After some experimentation, she believes that exploding oneself in the cave will break the time loop. Sarah offers Nyles a chance to escape with her, but he confesses his love for her and asks if they can stay in the loop together forever. She refuses, resolved to try her escape plan without him. Sarah attends the wedding one last time, giving a heartfelt speech to Tala, and then travels to the cave with explosives. Nyles has a change of heart, and rushes to the cave to leave with her. He declares that he would rather die with her in an explosion than remain in the loop alone. Sarah reciprocates his feelings, and they kiss in the cave, as she presses the detonator. The two then relax in the pool of a nearby house, which Nyles had shown Sarah during one of their loops. The residents return and catch them there, which seems to indicate that the plan has worked and it is now November 10. In a mid-credits scene, Roy, having gotten a voicemail from Sarah explaining her plan to escape the loop, returns to the wedding and asks Nyles if the plan would work. Nyles does not recognize Roy, who smiles, realizing that Nyles is out of the time loop.