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 film tells the story of a psychiatrist, Dr. Cross (Vincent Price), who is treating a young woman, Janet Stewart (Anabel Shaw), who is in a coma-state, brought on when she heard loud arguing, went to her window and saw a man strike his wife with a candlestick and kill her. It also stars Lynn Bari as Dr. Cross's nurse/lover, Elaine Jordan.
Three witnesses swear they saw Joe Reynolds murder grumpy baker Kenny (Ben Welden) with a hatchet. Joe claims Kenny's fatal head wound was the result of a fall as they argued—the baker hit his head on an oven as he fell—but the eyewitness testimony prevails and Joe is sentenced to death in the electric chair. His buddy Sam Lord has an uphill struggle to prove his innocence.
Sherry Conley (Ginger Rogers) is a model who is in prison for a crime she did not knowingly commit. She is offered a deal for her freedom by U.S. attorney Lloyd Hallett (Edward G. Robinson) if she will testify as a witness in the trial of mobster Benjamin Costain (Lorne Greene). Hallett hides her in a hotel under the protection of a squad of detectives led by Lt. Vince Striker (Brian Keith), where she stalls making a final decision while she enjoys expensive meals from room service. Despite the presence of the prison matron escort Willoughby, sparks begin to fly between cop and potential witness.
After five years in San Quentin prison, former policeman Steve Rollins is released. Unjustly convicted of manslaughter in an arrested man's death, Steve is met by a friend from the force, Dan Bianco, and by wife Marcia, whom he shuns because she has been unfaithful to him.
Professional football player Terry Brogan (Jeff Bridges) is released by his team, the (fictitious) Los Angeles Outlaws. Aging, injured and in need of money, he is contacted by an old acquaintance, the shady gambler and nightclub owner Jake Wise (James Woods), who wants Terry to find Jake's girlfriend Jessie Wyler (Rachel Ward), daughter of the Outlaws' owner. Jake claims that Jessie assaulted him, stole money and fled. Terry is reluctant to take on the job, but needs the money and knows Wise is capable of blackmailing him.
Art critic and forgery expert George Steele (O'Brien) is stopped by a policeman as he breaks into the Manhattan Museum. He claims that he was in a train wreck. Police Lieutenant Cochrane (Wallace Ford), however, finds that there has been no recent wreck. Steele, unsure himself what happened, relates the bizarre events leading up to the present. A flashback ensues:
Convict Van Duff is the leader of a large-scale prison break. The breakout works as the six survivors hide out in a forgotten mine working near the prison.
Giorgos Merkos (Giórgos Foúndas) est lieutenant de police. Il a tellement de travail qu'il ne peux trouver le temps de rencontrer les parents de sa fiancée Anna. Alors qu'il doit se rendre chez eux, il arrête un criminel et commence une autre enquête, sur le meurtre d'une femme d'âge mûr, Julia. Il soupçonne le jeune mari de celle-ci, Alekos Petratos mais ce dernier était dans le train de Thessalonique au moment du meurtre et la tante de la victime est allée le chercher à la gare. Giorgos Merkos ne croit pas à cet alibi et réussit finalement à confondre le mari. Plus tard, il est persuadé que le demi-frère d'Anna, Dimitris Naskos, est coupable d'un viol. Durant son arrestation, Dimitris cherche à s'enfuir. Il est tué par Giorgos. Il s'avère alors que Dimitris était innocent. Giorgos démissionne et perd sa fiancée.
Paul Hoplin is mastermind of a crime to collect a $500,000 ransom, threatening to use an explosive device that Jim Molner designed. He and his gang are holding Molner, wife Joan and young daughter Patty hostage.
A Korean War veteran is accused of the murder of a night club singer, in Tucson Arizona. A high school pin was found on the scene of the crime, and the veteran's pin is missing. However, when the crime was committed the veteran was leading a female somnambulist to her home, but her over-protective father gives a false testimony to the district attorney. "Slacks", a female friend, gives him a false alibi, but the police soon sorts that out. The veteran thinks that one of his fellow high school students from 1945 was the murderer. He has got possible suspects on a list.
A well known actress of the theatre was assassinated and the simultaneously one of these actors of the theatre escaped. The police along with the journalists of a newspaper company asked the edge of the filament for located the assassin. Quickly occurred evidently that the action occurred during the occupation period of World War II and the academy was sentimentally natural.
Eric Stanton (Andrews), a down-on-his-luck drifter, gets pulled off a bus in the hamlet of Walton because he does not have the $2.25 extra fare to take him to San Francisco. He finds a greasy spoon called Pop's Eats, where Pop (Percy Kilbride) is worried about waitress Stella because she has not shown up for work for days. Ex-New York cop Mark Judd (Bickford) tells him not to worry. Sure enough, the sultry Stella (Darnell) soon returns. Stanton (like the others) is attracted to her, but she is unimpressed by his smooth talk and poverty.
Boyhood friends and comrades in the Army, Ted Peters (Richard Attenborough) and Dave Robinson (Bill Rowbotham) are back in civvies. Ted becomes a taxi driver and hopes to marry Joy Goodall (Sheila Sim), a pretty chorus girl. Dave, seeking easy money, joins a gang which has its headquarters in a suburban palais-de-danse. The gang is headed by a man called Gregory (Barry Jones), and includes Paul Baker (Barry K. Barnes), and petty crooks Sniffy and Pogson. Ted refuses to join them.