The day after the party, Alice and Bill smoke marijuana and talk about their encounters at the party. The conversation escalates and Alice confesses to Bill her feelings concerning a naval officer she saw while they were vacationing in Cape Cod. Because of Bill's self-assurance, out of spite she admits that she was willing to abandon her life and her future for one night with the officer. Shocked by this revelation, Bill suddenly receives a telephone call summoning him to a deceased patient's home. Bill goes to the apartment of the patient and the daughter, Marion (Marie Richardson), says she wants to give up her life to be with Bill. Bill resists her request and departs once Marion's boyfriend Carl arrives.
While wandering the streets, a group of rowdy men, taking him for a gay man, taunt him and rudely walk into him. Soon afterwards, a female prostitute named Domino (Vinessa Shaw) approaches Bill on the street and solicits him. Bill accepts, but a phone call from Alice cuts their business short after a brief kiss. Bill insists on paying anyway.
He happens upon a sign outside the jazz club where Nick is the featured piano player. As the two discuss things, Nick describes a party he played at the night before and at which he is to play again tonight. His interest piqued, Bill coerces Nick into divulging the secret party's requirements: a black robe with a hood, and a mask. He also learns the location and more importantly, the password: Fidelio.
Bill goes to the costume shop of an old friend only to find it has a new owner, Mr. Milich (Rade Šerbedžija). He bribes Milich to get him a costume immediately. Another sexually charged situation involving Milich's teenage daughter (Leelee Sobieski) and two Japanese men follows.
Afterward, Bill takes a cab to the party in a foreboding mansion on Long Island. What he finds inside is a hierogamy-inspired sexual ritual (orgy) involving beautiful women clad only in masks and G-strings and led by an ominous man dressed and masked in red (Leon Vitali). Men (and women) watch, masked and clad in black robes, reminiscent of a Venetian Carnival. During the ritual, Nick plays the organ blindfolded. As the women rise from a circle surrounding a priest-like figure, they select men from the audience. One of the masked men in the audience stares directly at Bill for a short amount of time, and a mysterious woman standing next to the former later on selects Bill and informs him that he is in great danger, and urges him to leave immediately, but he refuses.
He is soon discovered as an outsider and forced to remove his mask, revealing his identity in the presence of the entire assembly. The red-robed master of ceremonies demands that he disrobe, but his apparently pending "punishment" is "redeemed" by the same mysterious woman (Abigail Good) who had tried to warn him earlier. Bill is threatened to remain quiet about what he saw or suffer dire consequences, then is released and returns home.
When Bill arrives home, he finds Alice laughing in her sleep. After waking her, she tells him of her horrible dream. She was having sex with a number of other men, and she knew that Bill was watching, and so she laughed at him.
The following day, Bill decides to investigate what happened the previous night. He goes to the hotel at which Nick was staying and finds out from the front desk clerk that Nick has apparently been brutalized for telling Bill about the party and password, and is now gone. He then returns to the mansion, but is warned off. Bill returns the costume to the shop from which he rented it, and the owner of the costume shop offers his daughter to Bill as a prostitute. Bill goes to Domino's apartment where he learns from her roommate that Domino received results of a blood test, which said she was HIV positive. Additionally, Amanda Curran, the young woman who "redeemed" Bill, is dead, ostensibly of a drug overdose behind a locked apartment door. Bill goes to the morgue and learns this woman is actually Mandy, whom Bill had helped to revive at Ziegler's Christmas party. He is unable to establish definitively that the woman did indeed die simply of a drug overdose. Bill is then called to Victor Ziegler's home, where the millionaire claims that he was one of those present at the ritual the previous night and that nothing further was done; according to him, Amanda was a drug-addicted prostitute and Nick was allowed to leave without further punishment. Both here and in the orgy scene it is implied, though never said explicitly, that Ziegler was indeed the masked man staring at Bill and that he summoned Amanda to "redeem" his friend. No conclusive evidence is presented, however, concerning the actual fate of both Amanda and Nick, and both Bill and the audience are left to decide between the explanation given to him or a (possibly double) murder. Ziegler does warn Bill against investigating further, as some of the masked participants are said to be extremely powerful members of society.
Bill returns home later to Alice and finds that the mask he wore to the party is lying on the pillow next to her. He breaks down crying, waking Alice before confessing to her about his journey. While Christmas shopping later that morning, Alice shows that she has come to terms with Bill's actions by accepting that one night does not reflect his entire persona. Finally, Alice suggests that they need to do one very important thing soon: "Fuck."
In a special edition of the television show Roger Ebert & the Movies, director Martin Scorsese named Eyes Wide Shut his fourth favorite film of the 1990s. For the introduction to Michel Ciment's Kubrick: The Definitive Edition, Scorsese wrote: "When Eyes Wide Shut came out a few months after Stanley Kubrick's death in 1999, it was severely misunderstood, which came as no surprise. If you go back and look at the contemporary reactions to any Kubrick picture (except the earliest ones), you'll see that all his films were initially misunderstood. Then, after five or ten years came the realization that 2001 or Barry Lyndon or The Shining was like nothing else before or since.
People who knew the director well, however, claim otherwise. Jan Harlan, Kubrick's brother-in-law and executive producer, reported that Kubrick was "very happy" with the film. According to Todd Field, Kubrick's friend and an actor in Eyes Wide Shut, Ermey's claims are slanderous. Field's response appeared in an October 26, 2006 interview with Slashfilm.com:
The polite thing would be to say 'No comment'. But the truth is that... let's put it this way, you've never seen two actors more completely subservient and prostrate themselves at the feet of a director. Stanley was absolutely thrilled with the film. He was still working on the film when he died. And he probably died because he finally relaxed. It was one of the happiest weekends of his life, right before he died, after he had shown the first cut to Terry, Tom and Nicole. He would have kept working on it, like he did on all of his films. But I know that from people around him personally, my partner who was his assistant for thirty years. And I thought about R. Lee Ermey for In the Bedroom. And I talked to Stanley a lot about that film, and all I can say is Stanley was adamant that I shouldn't work with him for all kinds of reasons that I won't get into because there is no reason to do that to anyone, even if they are saying slanderous things that I know are completely untrue.
The version released in Europe and Australia featured the orgy scene intact (theatrical and DVD release) with ratings mostly for people of 16 (Europe, in Germany) and 18+ (Australia) years of age. In New Zealand and in Europe, the uncensored version has been shown on public television without controversy. In Australia, it was broadcast on public television (on Network Ten) with the alterations in the American version for people of 15 years of age and older, blurring out, and cutting the images of explicit sexuality.
Roger Ebert has been widely misquoted as calling the standard North American R-rated version the "Austin Powers" version of "Eyes Wide Shut". This is presumably in reference to the two scenes in the first Austin Powers movie Austin Powers: International Man of Mystery in which through clever camera angles and unbelievable coincidences body parts are blocked from view in a comical way. In fact, Roger Ebert saw a very rough early draft of the altered orgy scene which was ultimately not used. It is this never-released version that he called the "Austin Powers" version, not the final R-rated version released in North America. Nonetheless many other discussions of the film have misquoted Ebert as saying the latter.
When Warner did not immediately concede, the American Hindus Against Defamation threatened to protest. Eventually, Warner Brothers came to an agreement with the Hindu community of Great Britain and edited the recitation of the passage out of the scene, replacing it with a different chant of similar dramatic tone. These changes were not made in the North American version.
The scene in which Kidman dances naked in front of a mirror has been zoomed in on DVD copies after Tom Cruise enters the room.
The earliest American DVD release of the uncut version states on the box cover that it includes both the R-rated and unrated editions; however only the unrated edition is actually on the DVD.