In the early to mid 20th century, a young woman named Mary Agnes reflects on the messy, dramatic life of her cousin Sherry. Though she refers to her as her cousin, Mary Agnes and Sherry have no blood relation. When Mary Agnes is six years old, a sick mother leaves her child, only a year older than herself, to stay with her family, and the mother dies soon after. So Mary Agnes's parents call the girl Mary Elizabeth and send her to Catholic school with their children. Mary Elizabeth is beautiful, with deep red hair, and she loves to be the center of attention, often singing and dancing for her peers during school, though most of the time it gets her in trouble. When the girls enter high school, Mary Elizabeth gets plenty of attention from their male peers and even older men in the town.

Towards the end of high school, Mary Agnes's father passes away, and she begins to consider herself the sad, ugly cousin. Mary Elizabeth continues getting in trouble at school and is eventually dismissed before graduating, at which point Mary Agnes's Aunt Lil takes her in to do housework. Mary Elizabeth is not allowed to leave the property, however, so Mary Agnes and her older brother Francis visit her in Aunt Lil's garden after school. One night, Aunt Lil finds Mary Elizabeth and Francis half-dressed on the couch downstairs. The next day, Mary Elizabeth leaves on a bus, and Mary Agnes, who at this point has left school and works at a zipper factory, doesn't see her again for months.

Eventually, Mary Agnes receives a postcard from her cousin, signed Sherry, whose new name was decided by a dancer at a nightclub because of the color of her hair. Mary Agnes tells her mother that she is working extra shifts on the weekends, but secretly takes the train to New York to visit Sherry. Over the years, Sherry has several different agents: always older men who help her find gigs dancing, singing, or acting around town. While Sherry is dating Tony, a saxophone player, Mary Agnes's visits are often spent talking with Sherry late at night, waiting for Tony to come home, who usually arrives around three or four A.M., several hours later than planned.

After Tony eventually leaves her, Sherry begins to date her new manager Harry, also known as the Colonel, and the two are soon married. Mary Agnes begins taking classes at Columbia and continues to see Sherry regularly, who is now seeing a therapist and learning about wine, cheese, and which utensil goes with which course of the meal. After a few years however, Sherry tells Mary Agnes that she is getting divorced during lunch one day, explaining that being part of Harry's world made her lose parts of herself.

After her divorce, Sherry moves into a new apartment with a pet parrot named Jamie. Sherry soon gets a roll in a big movie, and she excitedly shares the news with her friends and family. When the movie premiers, however, Sherry is only in the final scene. The next day, a cleaning lady finds Sherry dead from an overdose. Mary Agnes learns of her cousin's death and goes to her apartment with the Colonel and a friend. Mary Agnes considers taking something to remember her by, but decides against it, and the three leave, hoping the doorman will find something to do with the parrot.