Esther is an intern at a magazine in New York City.
With a fellow intern, Doreen, Esther ditches a magazine event in order to hang out with Lenny Shepard, a man who introduces himself as they are riding in their cab. As Doreen proceeds to hook up with Lenny, Esther heads back to their hotel residence and takes a long bath.
A few days later, Esther goes to a banquet held at Ladies' Day magazine for her and her fellow interns. That morning, she had had a distressing talk with her boss, Jay Cee, about her career plans. After the luncheon, Esther and the other interns get violently ill.
The next day, she goes on a date with Constantin, an interpreter at the UN whom she met through Mrs. Willard, her boyfriend Buddy's mother. Esther thinks over how her feelings for Buddy have changed over their history together.
She had started dating Buddy in college. At first, she admired him, despite his disparaging attitude toward her literary aspirations. She quickly lost her admiration for him when she found out about his affair with a waitress over the past summer.
On her date with Constantin, Esther feels an instant attraction. But the date ends with the two of them falling asleep fully clothed on his bed.
After Constantin drives Esther back to her hotel residence the next morning, Esther thinks back to how she broke her leg.
The past winter, she had visited Buddy at a sanatorium where he was staying because he had contracted tuberculosis. After rejecting his proposal of marriage, she and Buddy had gone to a ski slope, where Buddy attempted to teach her to ski. Esther accelerated down a hill and broke her leg in two places.
The last day of her internship, a photographer attempts to take Esther's portrait, but she breaks down in tears.
Later, Esther attends a country club dance with Doreen, where she's attacked by her date, Marco.
The next morning, Esther takes a train back home to Boston. Her mother picks her up at the train station, and announces that Esther hasn't made it into a summer writing program. Over the next couple of weeks, Esther quickly spirals downward into a deep depression.
Unable to sleep or work, she is referred to a psychiatrist, Dr. Gordon. After a couple of visits, Dr. Gordon subjects Esther to electroshock therapy, which only worsens Esther's condition.
Afterward, Esther takes a few practice runs at suicide. She practices with a blade in front of her bathroom mirror. She visits her old hometown by the shore and contemplates drowning herself. She tries strangling herself at home, but fails. She's invited to the beach by some friends, and swims out, but is unable to drown herself.
Esther attempts to take her mother's advice and find solace as a hospital volunteer. But she messes up her job distributing flowers in the maternity ward, and flees the hospital.
Esther visits her father's grave and breaks down in tears.
Eventually, Esther steals a bottle of sleeping pills from her mother's closet, burrows her way into a crawl space underneath the house, and swallows the pills.
Esther is rescued. At the first hospital she's taken to, Esther catches a glimpse of herself in a mirror and drops the mirror.
Esther is moved to the psychiatric ward of a city hospital. There, she trips up one of the attendants who serves meals and spills the thermometer tray when a nurse isn't looking.
Esther is finally moved to a private psychiatric institution, where she meets the sympathetic Dr. Nolan.
Later, Esther is joined by Joan, an old high school friend who was inspired by the press coverage of Esther's attempted suicide to attempt suicide herself.
Esther's condition improves with insulin shock therapy, and she's moved to a different residence within the institution.
She's surprised one morning to discover that she is scheduled for electroshock therapy that day. But this time, the therapy goes well under the guidance of Dr. Nolan.
At the residence, Esther discovers that DeeDee and Joan are having an affair.
Esther goes into town to get fitted for a diaphragm.
On a visit to Cambridge, Esther meets a Harvard professor and decides to lose her virginity to him. After they have sex, Esther starts to bleed profusely. Her friend Joan helps her to the emergency room, where Esther recovers.
A few days later, Esther is woken up in the middle of the night – she's told that Joan has committed suicide.
It is now January. Buddy visits Esther at the institution.
Esther attends Joan's funeral.
The novel ends as Esther enters her exit interview at the institution.