In early 1950s Los Angeles, Detective Sergeant Edmund "Ed" Exley (Guy Pearce), the son of a legendary LAPD detective, is determined to live up to his father's reputation. His intelligence, insistence on following regulations and cold demeanor contribute to his isolation from other officers. He exacerbates this resentment by volunteering to testify in a police brutality case, insisting on a promotion to Detective Lieutenant against the advice of Captain Dudley Smith (James Cromwell). Exley's ambition is fueled by the murder of his father by an unknown assailant, to whom he refers as "Rollo Tomasi" to give him personality.
The unnamed driver (Ryan Gosling), who lives in an Echo Park, Los Angeles apartment, works repairing cars and as a part-time movie double. Managed in both jobs by auto shop owner Shannon (Bryan Cranston), the duo also provides a getaway driver service. With Shannon organizing the events, the driver gives criminals only five minutes to perpetrate robberies and reach his car. After meeting his new neighbor, Irene (Carey Mulligan), the driver soon becomes close to her and befriends her young son, Benicio (Kaden Leos), while Irene's husband, Standard Gabriel (Oscar Isaac), is in prison. After her husband is freed, Irene still asks the driver to visit them.
During Prohibition in 1930s, Al Capone (De Niro) has nearly the whole city of Chicago under his control and supplies illegal liquor. Bureau of Prohibition agent Eliot Ness (Costner) is assigned to stop Capone, but his first attempt at a liquor raid fails due to corrupt policemen tipping Capone off. He has a chance meeting with Irish-American veteran officer Jimmy Malone (Connery), who is fed up with the rampant corruption and offers to help Ness, suggesting that they find a man from the police academy who has not come under Capone's influence. They recruit Italian-American trainee George Stone (Andy García) for his superior marksmanship and intelligence. Joined by accountant Oscar Wallace (Charles Martin Smith), assigned to Ness from Washington, D.C., they conduct a successful raid on a Capone liquor cache and start to gain positive publicity, with the press dubbing them "The Untouchables." Capone later kills the henchman in charge of the cache as a warning to his other men.
Anna Ivanovna, a British-Russian midwife at a London hospital, finds a Russian-language diary on the body of Tatiana, a 14-year-old girl who dies in childbirth. She also finds a card for the Trans-Siberian Restaurant, which is owned by Semyon, an old vor in the Russian Mafia. Anna thus sets out to track down the girl's family so that she can find a home for the baby girl, having meetings with Semyon, whom she initially regards as friendly. Anna's mother Helen does not discourage her, but Anna's Ukrainian uncle and self-described former KGB officer, Stepan, whom Anna asks for help with the translation of the diary, urges caution. Through translation of the diary, Anna comes to learn that Semyon and his ignorant therefore unstable son Kirill had abused the girl, addicted her to heroin, forced her into prostitution, and raped her. Ultimately, Anna realizes that the baby was fathered by Semyon (in several scenes it is made clear that Kirill is impotent and never had sex with Tatiana).
In Los Angeles, on January 15, 1947, LAPD officers Dwight 'Bucky' Bleichert (Josh Hartnett) and Lee Blanchard (Aaron Eckhart), investigate the murder and dismemberment of Elizabeth Short (Mia Kirshner), soon dubbed 'The Black Dahlia' by the press. Bucky learns that Elizabeth was an aspiring actress who appeared in a pornographic film. Through his investigation, Bucky learns that Elizabeth liked to hang out with lesbians. He goes to a lesbian nightclub and meets Madeleine Linscott (Hilary Swank), who looks very much like Elizabeth. Madeleine, who comes from a prominent family, tells Bucky that she was 'very close' with Elizabeth but asks him to keep her name out of the papers. In exchange for his silence, she promises him sexual favors. Continuing his relationship with Madeleine, Bucky meets her wealthy parents, Emmett (John Kavanagh) and Ramona (Fiona Shaw).
Henry Hill says, "As far back as I can remember, I always wanted to be a gangster", referring to his idolizing the Lucchese crime family gangsters in his blue-collar, predominantly Italian-American neighborhood in East New York, Brooklyn. Wanting to be part of something significant, Henry quits school and goes to work for them. He is able to make a living for himself and learns the two most important lessons in life: "Never rat on your friends, and always keep your mouth shut", the advice given to him after being acquitted of criminal charges early in his career.
Marv (Mickey Rourke) regains consciousness on a highway overlooking the Projects, surrounded by several dead young men and a crashed police car, and with no memory of how he got there. He retraces his steps, recalling that since it's Saturday, he watched Nancy Callahan (Jessica Alba) dance at Kadie's Saloon. Stepping outside, he encounters four rich frat boys burning a homeless man alive. When Marv intervenes, the leader of the frat boys shoots him in the arm, calling him "Bernini Boy," which Marv mishears as "Bernie." They flee; Marv follows, stealing a Police car on the way, which he crashes into their car, leading to his blackout and memory loss. He follows the two surviving frat boys into The Projects, the neighborhood where he grew up. With the assistance of the deadly residents lurking in the shadows, he dispatches the frat boys. He questions the leader about being called "Bernini Boy" and learns that it is the brand of coat he is wearing. After slitting the boy's throat, he considers his coat and realizes he can't remember how he acquired it.
A woman identifying herself as Evelyn Mulwray (Ladd) hires private investigator J. J. "Jake" Gittes (Nicholson) to carry out surveillance on her husband, Hollis I. Mulwray (Zwerling), chief engineer for the Los Angeles Department of Water and Power. Gittes tails him, hears him publicly oppose the creation of a new reservoir, and shoots photographs of him with a young woman (Palmer), which are published on the front page of the following day's paper. Upon his return to his office, Gittes is confronted by a beautiful woman who, after establishing that the two of them have never met, irately informs him she is the real Evelyn Mulwray (Dunaway) and that he can expect a lawsuit.
The story takes place involving three different people who all work together in the same supermarket over the 24 hour period leading up to Christmas. Ronna (Sarah Polley) is broke and about to be evicted from her apartment. Despite having worked for 14 hours, she agrees to take her British co-worker Simon's (Desmond Askew) shift. While working, she's approached by two men, Adam (Scott Wolf) and Zack (Jay Mohr), who ask if she can come up with 20 hits of ecstasy, which they were hoping to buy from Simon. Realizing she can make some money from the deal, she goes to Simon's dealer Todd Gaines (Timothy Olyphant). Because she doesn't have enough money, Ronna has to leave her friend and co-worker Claire (Katie Holmes) with Todd until she makes her deal. Once she tries to make the deal, she grows suspicious when Burke (William Fichtner), a person she never met before and who is with Adam and Zack, presses her for the drugs. In a panic, she flushes the drugs down the toilet and manages to get out. Ronna then swaps the pills she flushed with aspirin pills she steals with the help of Mannie (Nathan Bexton), Ronna and Claire's friend (and also co-worker in the supermarket), who had swallowed two of the pills without knowing their strength. Ronna hands off the pills to Todd and she, Claire and Mannie make their way to a rave party. Todd soon realizes that he's been given fake pills and goes after Ronna. Mannie sees Todd coming and Ronna hides Mannie when he starts to become sick. In the parking lot of the party Todd confronts Ronna, but before he can shoot her a car runs her over and dumps her off the side of a small cliff, leaving her fate unknown.
After a rooftop chase, where his acrophobia and vertigo result in the death of a policeman, San Francisco detective John "Scottie" Ferguson retires. Scottie tries to conquer his fear, but his friend and ex-fiancée Midge Wood suggests another severe emotional shock may be the only cure.
Three friends, Arlene, Shanna and radio DJ "Jungle" Julia Lucai, drive down Congress Avenue in Austin, Texas on their way to celebrate Julia's birthday. In a bar, Julia reveals that she made a radio announcement offering a free lap dance from Arlene in return for addressing her as "Butterfly," buying her a drink, and reciting a segment of the poem "Stopping by Woods on a Snowy Evening". Aging Hollywood stunt double "Stuntman Mike" trails the women to a bar and claims the lap dance. Arlene is suspicious, having seen Mike's car earlier that day, but Mike puts her at ease.
Alicia Huberman (Ingrid Bergman), the American daughter of a convicted Nazi spy, is recruited by government agent T. R. Devlin (Cary Grant) to infiltrate an organisation of Nazis who have moved to Brazil after World War II. When Alicia refuses to help the police, Devlin plays recordings of her fighting with her father and insisting that she loves America.
In 1949, Ed Crane (Billy Bob Thornton) is a low-key barber in the town of Santa Rosa, California. He is married to Doris (Frances McDormand), a bookkeeper with a drinking problem, and works in a barber shop that belongs to his brother-in-law Frank (Michael Badalucco). A customer named Creighton Tolliver (Jon Polito) tells Ed that he's a businessman looking for investors to put up $10,000 in a new technology called dry cleaning. Ed decides to get the money by anonymously blackmailing Doris's boss, "Big Dave" Brewster (James Gandolfini), whom he knows to be having an affair with Doris. Dave embezzles money from his department store to pay the blackmail. However, he soon pieces together the scheme and beats Tolliver until he implicates Ed. Dave confronts Ed at the store and attempts to kill him, but Ed stabs Dave fatally with a cigar knife.
The film begins in noir fashion when Easy Rawlins (Denzel Washington) says, "A man once told me that when you step out of your door in the morning, you're already in trouble. The only question is, are you on top of that trouble or not?"
The film is a satire on the modern advertisement business. The plot mainly concerns the story of a commercial advertisement designer, Octave Parango (Jean Dujardin), who has an easy-going, highly paid job, and an active free life mainly consisting of drugs and random one-time sexual relationships. However, he starts growing weary of his job, and after having his first ever long-time relationship with fellow worker Sophie (Vahina Giocante) fail miserably, he organises a revolt against the advertisement business and his own life.