Sara is the tragically lonely and addicted mother of Harry Goldfarb. Without her son and her husband around, Sara spends almost all of her time watching television. She becomes addicted to diet pills and starts hallucinating.
In the Summer, Sara mostly stays in her apartment getting fatter while ironically watching an infomercial on weight loss. The infomercial is "Tappy Tibbons Month of Fury." It's on every time she turns on the television. She gets a call saying that she's been chosen to be on television. She fills out an application and spends the rest of her time waiting a response. She wants to wear the red dress she wore to her son's high school graduation, but she cannot fit into it. She starts a diet but is unwilling to continue and instead starts taking diet pills.
The pills make her incredibly energetic and she starts losing weight. Unfortunately, many side effects similar to amphetamines or stimulants start showing up. She begins grinding her teeth, compulsively cleaning and talking, and eventually starts having hallucinations. She builds up a resistance and starts taking more pills at a time. While watching the Tappy video, she sees herself in the video. Her refrigerator becomes sentient and tries to eat her as her apartment turns into a television set. She begins wandering the streets of New York saying she's going to be on television and asking for Madison Avenue. When she gets to the television studio she is taken away by police and involuntarily taken to a mental hospital. She undergoes several types of treatment with no results. She is given electroconvulsive therapy at the film's ending montage. The film ends with her in her bed imagining herself on Tippy's informercial with Harry.