L'histoire se déroule en 1981, à Gotham City. Arthur Fleck travaille dans une agence de clowns. Méprisé et incompris par ceux qui lui font face, il mène une morne vie en marge de la société et habite dans un immeuble miteux avec sa mère Penny. Un soir, il se fait agresser dans le métro par trois hommes alcoolisés qui le brutalisent, le poussant à les tuer en retour. Son geste inspire à une partie de la population l'idée de s'en prendre eux aussi aux puissants ; Arthur bascule peu à peu dans la folie et finit par devenir le Joker, un dangereux tueur psychopathe victime d'hallucinations.
Twenty-year-old Will Hunting (Damon) of South Boston is a self-taught, genius-level intellect with an eidetic memory, though he works simply as a janitor at the Massachusetts Institute of Technology, and spends his free time drinking with his friends, Chuckie (Affleck), Billy (Cole Hauser) and Morgan (Casey Affleck). When Professor Gerald Lambeau (Skarsgård) posts a difficult problem taken from algebraic graph theory as a challenge for his graduate students, Will solves the problem anonymously, stunning both the graduate students and Lambeau himself. As a challenge to the unknown genius, Lambeau posts an even more difficult problem and chances upon Will solving it. Fearing he will lose his sole means of (a meager) income, Will flees and skips going into work the next day. That night, Will meets Skylar (Driver), a British orphan about to graduate from Harvard, who plans on attending medical school at Stanford.
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.
Near the completion of his sentence in Sing Sing prison, Paul Vitti's life is threatened by assassins and corrupt guards while incarcerated. He fakes insanity and starts singing showtunes from West Side Story to get the attention of Ben Sobel, who previously hung up on him while attending his father's funeral. The FBI calls in Ben to see if Vitti is really insane. This appears to be the case, and the FBI approves Ben taking Vitti out of prison, into his own custody, for further therapy. On their way out in Sobel's car, Vitti reveals that he faked it. Needing some therapy himself after his father's death, a grieving Sobel talks Vitti into finding a regular job (as requested by the FBI). Vitti attempts to find a legitimate job (he tries a car dealer, a restaurant, and a jewelry store), but his rude manners and paranoia only complicate things further (which end up in him getting fired each time).
Kate Miller (Angie Dickinson) is a sexually frustrated housewife who is in therapy with New York City psychiatrist Dr. Robert Elliott (Michael Caine). During an appointment, Kate attempts to seduce him, but Elliott rejects her advances.
Sabina Spielrein arrives at the Burghölzli, the pre-eminent psychiatric hospital in Zurich, with a typical case of hysteria and begins a new course of treatment with the young Swiss doctor, Carl Jung. He is using word association and dream interpretation as part of his approach to Freud's radical new science of psychoanalysis, and finds that Sabina Spielrein's condition was triggered by the humiliation and sexual arousal she felt as a child due to her short-tempered father's habit of spanking her naked. These conflicting feelings were compounded by her instinctive knowledge (imparted by an angel's voice that speaks in German) that she had done nothing to deserve such a punishment and in fact that she may have been a stand-in for her mother in her father's abuse (since her mother was unfaithful). Also, her affluent Russian Jewish family afforded her an exceptional education in preparation for university study, although not on the subject of sex, and she was a virgin.
John Henderson (Albert Brooks) is a successful science fiction writer who is finalizing his second divorce. Perplexed by the issues he has with women, John decides to initiate a project that will help him understand what went wrong in his relationships—he moves back in with his mother (Debbie Reynolds), occupying the same bedroom he had as a child.
Leah Lemonnier (Josiane Balasko), 35 years ols, leads a dreary and depressing life between her work as secretary of a dentist who spends his time in scolded, her analyst (Richard Berry) who sees in it only a source of income, her neighbor, Mr. Schpil, sexually obsessed and party animal (Jean Benguigui) and his mother (Catherine Samie) nymphomaniac, selfish, greedy, narcissistic and contemptuous. But one day, she unwittingly invokes the devil. He have the face of a handsome devil, Abargadon says "Abar" (Daniel Auteuil), who offers her a deal: he starts her service until her death in exchange of her soul.
Chloé est une jeune femme très fragile et en pleine dépression. Elle entreprend alors une psychothérapie. Elle tombe rapidement amoureuse de son thérapeute, Paul, et ses sentiments sont partagés. La jeune femme paraît enfin épanouie. Quelques mois plus tard, le couple décide de s'installer dans un appartement commun. Chloé découvre alors que Paul lui a caché une partie de son identité. Il a en effet un frère jumeau, Louis, qui exerce la même profession que lui ...
Bob Weston works for STOP, a scandal magazine. His colleague has written a dirty article about Helen Gurley Brown, the author of a best-selling new book with advice to single women on how to deal with men, calling her a virgin. She is very offended. Due to this article, Helen has lost six appointments. Weston wants to interview her, but she refuses to see him.
Eve White is a timid, self-effacing wife and mother who is subject to severe and blinding headaches and occasional blackouts. Eventually she is sent to see a personality psychiatrist Dr. Luther, and while having a conversation, a "new personality", the wild, fun-loving Eve Black, emerges. Eve Black knows everything about Eve White, but Eve White is unaware of Eve Black. When Eve Black becomes the dominant personality, Eve White's husband leaves her and abandons their daughter, Bonnie. Eve White is sent to an asylum after Eve Black tries to kill Eve White's daughter.
René a tué sa tante Jeanne, sans doute parce qu'elle tenait trop à voir en lui un criminel. L'avocate Solange le défend. Peu à peu, alors qu'elle voit en René son fils décédé, le fantôme de Jeanne s'incarne en elle. René est acquitté. Ils deviennent amants. Mais après une vie en commun intolérable, c'est elle qui, pour finir, le tue...
L'histoire conte l'apparition de symptômes névrotiques chez Martin Fellman, chimiste, marié, de la bourgeoisie joué par Werner Krauss. Après des pérégrinations entre cauchemars, rêves, fantasme de meurtre de sa femme et autre sentiment de culpabilité, il rencontre par hasard un psychanalyste, le Dr Orth, joué par Pavel Pavlov qui, par la cure psychanalytique, parviendra à le guérir.
Dr. John H. Watson (Robert Duvall) becomes convinced that his friend Sherlock Holmes (Nicol Williamson) is delusional—particularly in his belief that Professor James Moriarty (Laurence Olivier) is a criminal mastermind—as a result of his addiction to cocaine. Indeed, Moriarty visits Watson to complain about being harassed by Holmes. Watson enlists the aid of Sherlock's brother, Mycroft (Charles Gray), to trick Holmes into traveling to Vienna, where he will be treated by Sigmund Freud (Alan Arkin). During the course of his treatment, Holmes investigates a kidnapping case with international implications, and Freud uncovers a dark personal secret suppressed in Holmes's subconscious.