After a year's seclusion in Maraneck State Hospital in New England, twenty-six-year-old Charlotte Bronn is ready to return home. Her husband Arnold is warned by Dr. Collins that many patients come back within a year, because they return to the same situation that precipitated the breakdown. Collins worries that Charlotte holds a deep resentment towards her stepsister, Joan Carlisle, who lives with them, but Arnold assures him that they got along well before Charlotte's hospitalization. When the childlike Charlotte greets Arnold, he acts reserved, and on the drive home to Cape Marble, Massachusetts, he mentions they have a boarder, Jack Diamond, the first Jew on the faculty of the college where Arnold teaches. Arnold, who says he has always been against anti-Semitism, relates that some of the faculty members have been critical of Jake, as they do not want an influx of Jews. He also reveals that he hopes to be promoted to head of the philosophy department by ingratiating himself with Jake's sponsor. The next day, when Charlotte questions the reason Arnold did not spend the previous night in their bedroom, he lies that Dr. Collins suggested she should sleep alone for awhile. At dawn one morning, Charlotte goes to the shore, where she finds Jake, who is doing a lobster run for an older man. He invites her for coffee, and they find that they both feel like outsiders in the town. As they walk, the wife of one of Arnold's colleagues notices them together. Later, at a clothing store, Charlotte is humiliated when the proprietor makes her call Arnold to get his approval before she purchases a dress. When she asks Arnold to take a day off and spend it with her, he refuses. Jake decides not to go to a faculty gathering, and Arnold, offended and afraid that Jake's behavior will bode ill for his chance at the promotion, characterizes him to Charlotte as the type of person who likes to sneer at others. That evening, Jake finds Charlotte, who also has refused to go to the gathering, asleep in Arnold's study. As he covers her, she touches his hand, then embraces and kisses him. Awakening, she pushes him away, and he apologizes for accepting the kiss. When Arnold arrives home with Joan, Charlotte tries to kiss him, but he coldly pulls away. The next day, with a burst of energy, Charlotte announces she is joining Joan and her stepmother, Inez Winthrop, on a shopping trip to Boston. Charlotte runs into Hamilton Gregory, a former classmate, whom she rejected in favor of Arnold, who was then her professor. Hamilton, who has become an alcoholic, invites her to his apartment, where he indelicately implies that Arnold is having an affair with Joan. Some time later, when her friend Cathy Bergner, who is going through marital difficulties, asks Charlotte for advice concerning what she did when she learned about Arnold's affair with Joan, Charlotte is shocked, as Joan assured her recently that there had never been anything between her and Arnold. She walks five miles through the snow to Arnold's college, then interrupts a meeting to question him. Charlotte protests to the uncomfortable Arnold that if he wants her to get well the two of them should go away together. He finally agrees to take her to Boston over the Christmas holidays, as he needs to see people at Harvard regarding the promotion. In their Boston hotel room, Arnold loses his temper with Charlotte. She then meets Hamilton, and when she tells him that she suspects Arnold is drugging her, he realizes something is wrong. He tries to set up an appointment for her with a psychiatrist, but she leaves him and instead goes to a beauty salon, where she has the owner dye her hair blonde and braid it in the back, like Joan. She next sees a gown that looks like one of Joan's, and though it is much too large, she buys it. Later, meeting Arnold and his guests in the hotel dining room, she introduces herself as Joan, then trips and loses a shoe, creating a scene. Arnold carries her to their room, then cries when he is alone. Later that evening, Charlotte begs her husband to admit he does not love her, saying she can only save herself if she knows she is not deluded in that belief. When he calls her love an obsession, she bites his hand, after which he acknowledges that he no longer loves her. Charlotte agrees to wait a month before seeking a divorce so there will be no scandal that could jeopardize his promotion. After returning home, she finds Jake by the shore, and he relates that Arnold killed the last chance he had to stay at the college when he learned it was not to his advantage to support him. He says he has found a job in New York at a magazine and asks her to join him. Saying she is the last thing he or anybody needs, Charlotte refuses, but asks him to come to the New Year's dance to be her moral support. At the dance, people stare at the two of them together, and when Arnold insults her and looks longingly at Joan, Charlotte tells him to "go to hell." She then leaves with Jake, who kisses her and tells her that he will be at a hotel if she needs him. When Arnold and Joan return home, Charlotte confronts Joan for lying. Resolving not to blame Arnold, Joan or herself for her breakdown, she nonetheless tells Arnold she does not love him and Joan that she hates her. Charlotte packs and calls Jake to ask him to drive her to Boston. She then calls Hamilton to have him find her a place to stay and make an appointment with a doctor. Finally, she tells Arnold that she will file for divorce in Boston after the semester break, and that she expects him to move out of her house, which she is closing down. Outside she cries, but after Jake arrives and hugs her, they drive off together.