The title of the film refers to the duration of a relationship between Wall Street professional John Gray (Mickey Rourke) and divorced SoHo art gallery employee Elizabeth McGraw (Kim Basinger). The two meet and have a volatile and somewhat kinky sex life involving a variety of sexual and erotic acts. The film details a sexual downward spiral as John pushes Elizabeth's boundaries toward her eventual emotional breakdown. He often manipulates her into getting what he wants during sex and sometimes abuses her.
When Elizabeth, an attractive divorcee and art gallery employee and her friend Molly (Margaret Whitton) organize dinner with friends, they go to the market where Elizabeth sees John (Mickey Rourke), a handsome Wall street broker. Later, Elizabeth goes to a street market. She intends to buy a scarf, but it's too expensive. She meets John again and instantly feels attracted to him. He wins her over when he wraps her with the expensive scarf she wanted to buy.
They start dating, and John shows himself to be peculiar. He starts to blindfold Elizabeth, who is reluctant to go with John's desires, but agrees. John is loving and playful; he gives Elizabeth a watch, and he tells her to think about him at 12 p.m., which she does at work. In fact, she plays with herself thinking about all the things she had done with John. They also play with food, and these experiences make Elizabeth feel like a new woman. However, John is reluctant to meet Elizabeth's friends, and he excuses himself by telling her that he does not share her with anyone.
Elizabeth starts feeling confused, and her confusion increases when she is left by John at his apartment. Going through his belongings she finds a picture of him with a woman in his well organized closet, John calls her, and asks her if she went through his stuff, claiming that he will punish her if she did. When John arrives to his apartment, they have a confrontation about it, but they end up having sex.
John acts as a loving boyfriend, but at the same time, starts controlling Elizabeth by changing her wardrobe without even asking her opinion. Their sexual intensity grows, and they start having sex in public places.
One day, Elizabeth sees John, and she follows him to his office. He acts serious so she leaves feeling humiliated about the awkward manner John treated her. John stops her, and they go to a bar. There, Elizabeth tells him that she wants to feel like a man. John tries to please her, by buying her a suit, and they go to a bar for a drink. After they leave the bar, they are insulted by two guys in a car that believed them to be a gay couple. Elizabeth confronts them, and the guys chase them down an alley. Elizabeth and John fight them; Elizabeth is able to take a knife from one of the attackers, and stabs one of them as John fights the other guy. Eventually, Elizabeth and John win the fight, and they make love passionately.
John's sexual games go to a different level when he buys a mattress and a horse whip which Elizabeth uses in a strip tease for John. John becomes more aggressive in his sexual games, and he intimidates Elizabeth.
On her gallery's show day, Elizabeth sees her ex-husband, which makes her feel uncomfortable and melancholic at the same time. She asks Molly to tell him that she is not available to see him, but Molly reminds her that she is dating him, and that he is there for her, not Elizabeth. She starts feeling lonely, and she hears a message from John arranging a date at a hotel. When Elizabeth arrives to the hotel room, John blindfolds her. Then, a Latina prostitute enters the room, and she starts caressing Elizabeth and telling her to relax in Spanish as John observes them. The prostitute removes the scarf from Elizabeth's eyes, who acts apprehensively, paralyzed by this situation. John starts flirting and kissing the prostitute until Elizabeth reacts, and attacks the other woman. John is able to separate them, and Elizabeth leaves the hotel. She walks around the neighborhood of the hotel and realizes it is a sex spot. John follows her to a sex shop where she is in the middle of a crowd of men watching porn. She soon realizes that John is there and kisses another man to make John feel jealous, but she soon feels bad, and goes back to John who kisses and hugs her.
Elizabeth decides to go to the art show that was taking place simultaneously. Nevertheless, she does not feel well, and goes to John's. They make love, and then Elizabeth decides to leave. John realizes that he is about to lose her, so he opens up by telling her that he has five brothers and his mom used to work as a clerk. Elizabeth tells him that it is too late for him to change, and leaves. John is left devastated, and he tells himself that he will count to 50 for her to come back. As John starts counting, Elizabeth leaves his apartment and walks through the city crying, knowing that she finally ended a passionate but destructive relationship with John, a man who did not know how to love her.