There's a married couple named Paul and Elaine cleaning up after a party at their house. It's very late and both are drunk. They have a passive-aggressive tiff about Paul's obvious crush on their friend's new girlfriend, and Paul tries to have sex with Elaine, but she threatens to kill him with a knife—she even draws blood when she has her blade against his throat. She doesn't know that Paul already set up a phone call with that girlfriend he likes.
The next day, Paul gets a call from his friend's girlfriend. Elaine goes to her friend Liz's house. Liz is their babysitter's mother (the sitter is named Jennifer). In the evening, they attend another party, leaving their two boys home with Jennifer; this time it's a barbecue at their friend George's house. Paul takes Jennifer home upon their arrival, and in the car, he asks, "What does my wife do at your mother's house?" The daughter says in vulgar language that the two women are lovers and she goes over to get laid.
Elaine's mother visits because she can't stand to stay another night with Elaine's father. After Elaine's mother retires in the evening, the two have sex in the living room, but both of them are unimpressed by the sex. After a day, Elaine's mother feels better and returns to her own house. In the morning Paul has phone sex with his friend and his friend's girlfriend.
Then, that day, the couple are standing around grilling their food, and the decide that they don't like their life, so they knock the grill into the house and throw gasoline on the wall of the house. Then they go to dinner with their kids as the house burns down. That night, at a motel of course, the two really connect and feel like friends again.
