Molly Bolt first learns she is a bastard when she is seven years old, living with her adoptive parents in poor, rural Coffee Hollow, Pennsylvania. A sharp child, she devises a moneymaking scheme one day after finding out that her friend Broccoli Detwiler has an odd-looking penis. Molly charges a nickel to look at Broccoli’s penis and a dime to touch it. The business thrives among Molly’s schoolmates until Earl Stambach, another classmate, tattles on her to their teacher, Miss Martin. Miss Martin tells Carrie, Molly’s adoptive mother, who explodes with rage when Molly comes home from school. Among insults and rebukes, Carrie tells Molly she is a bastard, the daughter of a slut named Ruby Drollinger.
Molly spends much of her early childhood playing with her slow-witted cousin, Leroy. Together, they work on the family farm, picking bugs from the potato patch and devising schemes to torment Earl. Even at this point in her life, Molly knows she is different from others. She is dark-featured, whereas others are fair, and she is more intelligent and athletic. Carrie urges her to be more ladylike, but Molly runs around with the boys, feeling unrestricted by the conventional rules of gender that dictate she should like playing with dolls or playing nurse.
Shortly after the incident with Broccoli, Leroy’s mother, Jenna, has a baby and names him after Molly’s kind adoptive father, Carl. The baby dies after only two days, however, and Jenna dies a few weeks later of cancer. She’d known about the cancer for a while but kept it secret from her husband, Ep, because she knew the family couldn’t afford a doctor. The night of Jenna’s funeral, Molly wants to sleep next to Leroy to comfort him, but Carrie tells her that boys and girls aren’t allowed to sleep with each other.
In sixth grade, Molly develops a crush on a female classmate named Leota B. Bisland. They become friends, and through Molly’s urging, they begin to kiss in the woods after school every day. When Molly finds out her family is moving to Florida to look for work, she and Leota make love before separating.
Molly and Leroy’s families move to the Fort Lauderdale area, where Carl and Ep find jobs that split up Molly and Leroy. At school, Molly quickly learns the differences between the posh, bright-eyed rich students and the poor, who seem slovenly in spirit as well as in appearance. As the years pass, Molly uses her intelligence and sense of humor to become popular among the wealthier children, while Leroy becomes more like a redneck. Tension develops between them, but they try to remain close. Molly has her first heterosexual experience with Leroy after he tells her one day that he’s had repeated sexual experiences with an older man named Craig.
By the time Molly is a high-school upperclassman, she and Leroy have grown apart and do not have sex anymore. Molly belongs to the ruling clique at school, complete with social club membership and football-player boyfriend. She also obtains financial support from the school administration for a successful bid as class president after catching her principal in an adulterous affair with another teacher. The only snag in Molly’s junior year comes from Carrie and Carrie’s sister, Florence, who frequently criticize Molly for her arrogance, obstinacy, and apparent lack of feeling when Carl dies. Though their unjustified antagonism upsets her, Molly remains unapologetic about how she lives her life.
When Molly is a senior, she has an affair with Carolyn, one of her two best friends and captain of the cheerleading squad. Carolyn becomes so enraptured with Molly that she becomes jealous when Molly spends time with her other best friend, Connie. Carolyn accuses Molly of sleeping with Connie, which Connie overhears, forcing Molly to explain to Connie that she and Carolyn have been lovers. Connie says she can no longer be Molly’s friend, and Carolyn, upset with being called a lesbian, says Molly is the real lesbian because she isn’t feminine. The girls stop talking to each other.
The following fall, Molly attends the University of Florida on a full scholarship. She befriends her roommate, Faye Raider, a rich freshman who wants only to drink and carouse. When they begin an affair midway through the first semester, they ignore their social obligations in favor of spending time together in bed. Other girls notice and tell the dean of female students, Dean Marne. Dean Marne offers to help Molly with her problem, but Molly accuses her of hypocrisy and calls her a closet fairy. Angered by Molly’s insolence and concerned about her own reputation, Dean Marne commits Molly to a sanitarium for a few days. When Molly emerges, she gets a letter revoking her scholarship for “moral” reasons and finds Faye gone from school.
Unable to stay in school and unwelcome in Carrie’s house, Molly hitches a ride to New York City, where she believes she can make a better life for herself. Penniless, she spends her first nights in an abandoned car with Calvin, a young black man who fled from his parents because they found out he is gay. Calvin introduces Molly to his friends, shows her where she can get free meals, helps her make money, and brings her to a lesbian bar. When he leaves abruptly for San Francisco, Molly finds a ramshackle apartment in the West Village and a waitress job at the Flick, a burger joint where the waitresses dress like Playboy bunnies. There, she meets Holly, a voluptuous black lesbian.
Before meeting Holly, Molly unhappily fritters away her days at the Flick and her nights at truck-driver-filled lesbian bars where butch lesbians accost her for easy sex. But with Holly, Molly begins to see the more glamorous side of lesbian New York. Holly is a “kept” woman, receiving an allowance to be another woman’s lover. She encourages Molly to do the same and brings her to a party to meet Chryssa Hart, an eminent lesbian archaeologist. Chryssa offers to support Molly in exchange for her sexual companionship, but Molly refuses, even though she knows she could use the money to enroll in film school—her great passion. Instead, Molly labors to win a scholarship from New York University and works nights to pay the rest. This decision causes tension between Holly and Molly, and they argue the night Holly gets both herself and Molly fired from the Flick. Unable to reconcile her insecurity about the shallow life she leads with Molly’s industriousness, Holly leaves Molly.
Molly finds a job at Silver Publishing Company, reducing her class load to work during the day. She is promoted to the editorial staff and meets Polina Bellantoni, a lovely middle-aged professor writing a book about the Middle Ages. Molly immediately determines to have a relationship with her, but Polina has a husband, daughter, and male lover, and she is uncomfortable with Molly’s sexuality. She eventually relents, eager to explore her bisexual side, but her sexual fantasies of being a man repulse Molly. Trapped in a relationship with Polina, Molly begins an affair with Polina’s teenage daughter, Alice. Alice and Molly keep their tryst a secret until one day, in a tantrum, Alice tells Polina she and Molly are lovers. Polina sends Molly away, forbidding Alice to fraternize with her.
Demoralized by her experiences in New York, Molly escapes to her hometown in Pennsylvania. She meets Leota again, who now has two children and looks unnaturally aged. Leota is harsh with Molly about their shared sexual experience and thinks Molly is mentally disturbed for being a lesbian. Molly leaves Leota and never sees her again.
Back in New York, Molly decides to journey to Florida to film Carrie for her senior project, a documentary on Carrie’s life. Carrie is now completely alone and dying of cancer. She is overjoyed to see Molly, though she still disapproves of Molly’s sexuality. Carrie lets herself be filmed for a week, all that time telling Molly her thoughts, feelings, and dreams. Now, she thinks of Molly as her daughter and denies ever having said Molly is not hers. She tells Molly about her biological mother, Ruby, and her biological father, a French athlete from whom Molly seems to have received all of her physical traits. Molly leaves at the end of the week, having shot all her footage and made peace with Carrie.
Molly’s film does not impress her class, and the entire department is against her because she’s a woman. She graduates summa cum laude and Phi Beta Kappa but has trouble finding a job in the movie industry. She knows that many forces will prevent her from fulfilling her dreams of making films, but she resolves to continue striving.