Two years after the events of the previous film, Larry Daley (Ben Stiller) is now CEO of Daley Devices, a direct response television company that sells inventions inspired by his experiences as a night security guard at the American Museum of Natural History. While wealthy and successful, he has not had the time to see his museum exhibit friends in several months.
At the funeral of his son Marko and associates in Tropojë, Albanian mafia head Murad Hoxha vows to seek vengeance on his son's killer. Traveling to Paris with his men, he interrogates and tortures former intelligence agent Jean-Claude Pitrel, whose business card was found at the scene of Marko's death, but finds no information. He then bribes a corrupt police official for Pitrel's files and deduces that his old friend Bryan Mills was responsible and is in Istanbul.
In Reef City, an underachieving bluestreak cleaner wrasse named Oscar fantasizes about being rich and famous while making his way to work as a tongue scrubber at the local Whale Wash, a job in which he is following in his father's footsteps. Soon after arriving he is called to the office of his boss, a pufferfish named Sykes, to discuss the fact that he owes "five thousand clams" and has to pay it back by the next day. After explaining this to his angelfish best friend Angie, she offers him a chance to pay back the money by pawning a pink pearl that was a gift from her grandmother. Oscar brings the money to the race track to meet Sykes, but becomes distracted by his dreams of grandeur. Upon hearing that the race is rigged, he places it all on a long-shot bet by the name of "Lucky Day". Such a million dollar bet is noticed nearby by a beautiful lionfish named Lola, who flagrantly seduces an excited Oscar, but Oscar is disappointed when she leaves upon learning that he is a whale washer. Sykes is furious that Oscar bet the money but nonetheless agrees to see how the race turns out. Moments before their betted "horse" crosses the finish line, he trips and falls on the line.
As a child, Colin Sullivan (Damon) had been introduced to organized crime by Irish-American mobster Frank Costello (Nicholson) in the Irish neighborhood of South Boston. Over the years, Costello grooms him to become a mole inside the Massachusetts State Police, until Sullivan is accepted into the Special Investigations Unit, which focuses on organized crime.
Mitch McDeere (Tom Cruise) is a young man from an impoverished background, but with a promising future in law. About to graduate from Harvard Law School near the top of his class, he receives a generous job offer from Bendini, Lambert & Locke, a small, boutique firm in Memphis specializing in accounting and tax law. He and his wife, Abby (Jeanne Tripplehorn), move to Memphis and Mitch sets to work studying to pass the Tennessee bar exam. Avery Tolar (Gene Hackman), one of the firm's senior partners, becomes his mentor and begins introducing Mitch to BL&Ls professional culture, which demands complete loyalty, strict confidentiality, and a willingness to charge exceptional fees for their services. Seduced by the money and perks showered on him, including a house and car, he is at first totally oblivious to the more sinister side of his new employer, although Abby has her suspicions. Mitch passes the bar exam and begins working long hours that put a strain on his marriage. Working closely with Avery, Mitch learns that most of the Firm's work involves helping wealthy clients hide large amounts of money in off-shore shell corporations and other dubious tax-avoidance schemes. While on a trip to the Cayman Islands on behalf of a client, Mitch lets himself be seduced by a local woman. But the encounter is a set-up and their tryst on the beach is photographed by people working for the firm's sinister "head of security", Bill DeVasher (Wilford Brimley), who uses it to blackmail Mitch into keeping quiet about what he knows.
In 1968, Frank Lucas, the limo driver-turned-right-hand man of Harlem gangster Ellsworth "Bumpy" Johnson, inherits Johnson's gang when Johnson dies of a heart attack. Disliking the new, flashy gangsters of the neighborhood, Lucas decides to take control of Harlem's crime scene.
The opening screen says: "Some of this actually happened."
In 1978, con artists Irving Rosenfeld (Christian Bale) and Sydney Prosser (Amy Adams) have started a relationship and are working together. Sydney has improved Rosenfeld's scams, posing as English aristocrat "Lady Edith Greensly". Irving loves Sydney, though is hesitant to leave his unstable and histrionic wife Rosalyn (Jennifer Lawrence), fearing he will lose contact with her son Danny, whom Irving has adopted. Rosalyn has also threatened to report Irving to the police if he leaves her.
On the occasion of his daughter Connie's wedding, Vito Corleone hears requests in his role as the Godfather, the Don of a New York crime family. Vito's youngest son, Michael, wearing a Marine Corps uniform, introduces his girlfriend, Kay Adams, to his family at the reception. Johnny Fontane, a famous singer and godson to Vito, seeks his help in securing a movie role; Vito dispatches his consigliere, Tom Hagen, to Los Angeles to talk the abrasive studio head, Jack Woltz, into giving Johnny the part. Woltz is unmoved until he wakes up in bed with the severed head of his prized stallion.
Retired CIA field operative Bryan Mills attempts to build a closer relationship with his daughter, Kim, who lives with her mother, Lenore, and her wealthy stepfather, Stuart. While overseeing security at a concert for pop star Sheerah, Bryan saves her from a violent stalker. As a thank you, Sheerah offers to assess Kim's talent as a singer. Before Bryan can tell Kim, she asks her father for permission to travel to Paris with her best friend, Amanda. He initially refuses, but eventually agrees after Lenore pressures him. At the airport, he learns the girls are actually following U2 during their European tour, something Lenore knew but kept from him.
After killing Charles Floyd (Channing Tatum), FBI agent Melvin Purvis (Bale) is promoted by J. Edgar Hoover (Crudup) to lead the hunt for bank robber John Dillinger (Depp). Purvis shares Hoover's belief in using scientific methods to battle crime, ranging from cataloging fingerprints to tapping telephone lines.
On February 6, 1846, at Paradise Square in Lower Manhattan's Five Points, a territorial battle of hand-to-hand combat between Bill "the Butcher" Cutting's U.S.-born nativist gang, the Natives, and "Priest" Vallon's Irish Catholic immigrant gang, the Dead Rabbits, concludes when Cutting kills Vallon, witnessed by Vallon's young son, Amsterdam. Cutting declares the Dead Rabbits outlawed but orders that Vallon's body be buried with honor. Amsterdam seizes the knife used to kill his father, races off, and buries it along with a medal his father gave him. He is later raised at Hellgate orphanage.
Robert McCall (Denzel Washington) is a retired black ops operative who quietly lives in Boston, Massachusetts, works at a Home Mart hardware store, where he befriends many of his co-workers, and helps a security guard trainee named Ralphie pass his qualification exam. McCall promised his recently deceased wife that he would leave his old life behind. Unable to sleep, McCall spends some late nights reading in a 24/7 diner, where he befriends Alina (Chloë Grace Moretz), a teenaged prostitute for the Russian Mafia, who is regaled by Robert with his philosophical interpretations of the books he reads. One night she is hospitalized when brutally beaten by her pimp, Slavi (David Meunier). McCall enters a restaurant owned by the Russian mob and offers to buy Alina's freedom from Slavi for $9,800, but Slavi refuses, dismissing McCall as old and impotent. Failing in this approach, McCall kills Slavi and four of his men with skillful close combat efficiency.
Michael Sullivan Sr. (Hanks) is an enforcer for Irish mob boss John Rooney (Newman) in Rock Island, Illinois during the Great Depression. Rooney raised the orphan Sullivan and loves him more than his own biological son, the unstable Connor (Craig). Connor snaps and kills disgruntled associate Finn McGovern when meeting him with Sullivan, resulting in Sullivan gunning down McGovern's men. Sullivan's twelve-year-old son Michael Sullivan, Jr had hidden in his father's car and witnesses the event. Despite Sullivan swearing his son to secrecy and Rooney pressuring Connor to apologize for the reckless action, Connor murders Sullivan's wife Annie and younger son Peter, mistaking him for Sullivan, Jr. He then sends Sullivan to an ambush at a speakeasy but Sullivan realizes and escapes to Chicago with his son to seek Al Capone, for work and to discover the location of Connor, who has gone into hiding.
Mob boss Paul Vitti narrates a brief history of the Mafia: in the wake of Albert Anastasia's death, the dispute over who among Vito Genovese, Carlo Gambino and Joe Bananas will ascend to mob supremacy results in the Apalachin Meeting in upstate New York. The meeting is raided by the FBI, and the Mafia does not call a summit again until the present day.
In a filthy kitchen of an underground abortionist, an unkempt former medical doctor puts on surgical gloves and quickly downs a full glass of cheap whiskey. Face down on the kitchen table is a barely conscious Porter (Mel Gibson), severely wounded with two large bullet wounds in his back. The doctor pours whiskey on Porter's back to sterilize the area and digs out the bullets. Porter spends five months recuperating. Porter narrates that he had $70,000 taken from him and that is what he was going to get back.