The story starts in June 1925 on the beach resort of French Riviera, at the hotel near the city of Cannes. The family consisting of seventeen-year-old Rosemary Hoyt and her mother rent a room in the hotel to rest. Despite her young age, Rosemary is already an aspiring movie star who had the leading role in the popular movie named “Daddy’s girl”. But during the filmings Rosemary had to perform stunts with swimming in the channel of Venice several times and the cold water made her feel sick. So now her mother wants Rosemary to rest and heal. However, the young girl herself is enjoying the sun, the beach and the attention of the men. Suddenly she meets the man named Dick Diver, who is twice as old as she, and is immediately attracted to here. Dick immediately likes her too, but the trouble is that he came to the beach with his family: his stunningly beautiful wife Nicole and their two kids named Topsy and Lanier. The Divers have arrived with the company of their friends who are now constantly throwing parties. Dick and Rosemary start spending time together, but, despite his reassurances that it is nothing serious, Nicole immediately sees that Rosemary is deadly serious about her husband and he starts to fall for her too.
Soon, at the big party that takes place at the Divers’ home, a strange incident with three black men and one corpse involved happens. Violet McKisco, one of the friends of the Divers, sees something horrified in the bathroom and gets very loud and upset. The only guest who is able to keep calm is a war veteran, Tommy Barban. He tries to press Violet to keep silent about what she’s seen. But Violet’s husband, Albert, decides that Tommy is too rude with his wife and challenges Barban to a duel in the morning. Both men are lucky - they both miss, no one gets hurt and the issue is settled down.
Despite Nicole’s outburst, Rosemary continues to travel with the family and attending their parties. She departs with them to Paris and actively shows her affection to Dick there up to the attempts of seducing him. Dick resists, though, because, despite his feelings, he loves Nicole and his family and knows that his wife will be deeply hurt with this affair. Nicole, in her turn, sees everything perfectly, but she doesn’t want to disappoint her husband and ruin the party, so she behaves nice and hospitable to Rosemary. When in Paris, Rosemary finally turns eighteen and as an adult she is presented with her first champagne. Too bad that as an adult she again tries to have sex with Dick (he refuses).
One of the friends of the Divers, a musician named Abe North, has a depression episode and goes to the bar to get drunk. There he finds some troubles with the black men and the situation ends up with one of them being shot in Rosemary’s room. Dick, understanding that the corpse is a huge trouble, hides it somewhere and gives Nicole the blood-stained bedsheet from Rosemary’s room to dispose of. Nicole, naturally, thinks that Dick slept with Rosemary and now humiliates her with such a task, goes furious and throws a tantrum.
The body is transferred to the hall and Dick can now pretend to be a bystander who noticed it. Dick and Rosemary come to his suit to calm down, but suddenly they hear Nicole’s voice from the bathroom and it doesn’t sound healthy. They enter the bathroom and see Nicole talking oddly to herself and swaying. Rosemary thinks that it was the same strange thing, Violet McKisco was so afraid before.
The second book reveals the origins of Nicole’s strange behaviour. The book starts with the short description of Dick Diver - an aspiring young psychiatrist who has just got a degree and already have an almost finished book. He is discharged from the military and now can dedicate his life to science and career. In the spring of 1919 he transfers to Switzerland to work in the psychiatric clinic there with his friend, Franz Gregarovius, who invited him. Gregarovius wants him to see a young lady, a patient with the complicated symptoms who might be useful for finishing his book.
Dick has already written to the lady to understand better the nature of her disease. While travelling to Switzerland he remembers her letters she wrote back, innocently flirting with him and talking about her mental illness. When Dick finally meets Franz, he hears the full and horrible story. Nicole was brought to the clinic by her father, a man named Devereux Warren, at her sixteen. Nicole has schizophrenia, but her doctor, Mr. Dohmler, noticed that something should trigger the illness and this something is most probably connected with her father. Dr. Dohmler roughly interrogated Devereux and, when cornered, the man admitted that he raped Nicole since she turned twelve, after her mother’s death. Mr. Dohmler managed to receive order for Devereux to stay away from Nicole for five years, because their relationship may ruin her mental health completely. Nicole starts her life in the clinic and Franz admits that she is making a steady progress since she and Dick started their correspondence.
The story deeply touches Dick, but he is a professional, so he goes to the first meeting with Nicole, determined to resist any attempts to flirt with him. It appears to be incredibly hard: the young woman is overly sweet and is clearly attached to him. After a week Nicole says straight that she is in love with Dick and is sure that her improving mental state is the consequence of love. Dick still avoids any feelings towards her and tries to convince her that the reason of her improvement is the treatment, not love. Still, he gradually falls for Nicole. Dr. Dohmler notices this and lectures young psychiatrist, reminding him of ethics. Dick is torn apart by his feelings and duty, but he says that he has no plans for relationship with her. He manages to resist until the following summer. Then Dick realizes that he has completely and hopelessly fallen for his patient. Nicole is happy, but her rich and protective sister, who cared about her in the clinics, the woman named Baby Warren, is very cautious about him and their relationship, she clearly doesn’t approve it.
Nicole is considered relatively healthy now, she can go out of the clinic and she and Dick get married. Dick still works in the same clinic in Switzerland and finishes his book that is sold exceptionally well. Nicole gets pregnant and soon gives birth to a perfectly healthy baby boy they name Lanier. Dick and Nicole enjoy travelling and having fun a lot, everything seems great until Nicole’s second pregnancy that turns into a big relapse when Lanier’s sister, Topsy, is born. Dick manages to stabilize her, but we learn that she has something resembling a personality disorder and it’s a life-long illness: poor Nicole will never be fully healthy and the relapse can happen anytime after a significant event in her life. Nicole asks Dick to buy a mansion near Riviera (the one they had parties in the first book), so they can live in a calm place and she can get better and more stable while Dick continues his work. Nicole really wants Dick to achieve all his goals and doesn’t want to pull him back. She also wants to find a hobby for herself that may help her stabilize during her relapses. Her hobby appears to be throwing parties. That’s why they happen so often.
The narrative returns to the present time. Nicole and Dick return to their home from Paris. Dick invites Rosemary’s mother for a serious talk and says that he is in love with her daughter. Surprisingly, the woman approves this and says that she always encouraged Rosemary to be more persistent towards him. Dick then talks to Nicole, trying to explain her the situation, but because of the stress her mental state doesn’t allow to finish the talk and they spend some time alone. But they make up again and go skiing to Switzerland for Christmas holidays. On ski resort they meet Franz and Baby Warren. Franz has an idea to buy the clinic they worked in and make it his own private clinic. He offers Dick to be his partner. After some hesitation Dick decides that it will be a good investment. Nicole supports his decision and Dick finally agrees.
Despite they spend time together, the marriage problems don’t vanish. Dick starts drinking, Nicole becomes more detached from reality. Once Nicole receives a letter from an unknown woman. The woman accused her husband of seducing her teenage daughter, using his authority as a doctor. Nicole immediately calls Dick out, but he denies everything, saying that the woman is just trying to blackmail him. But from his thoughts we learn that Dick indeed kissed her teenage daughter. Nicole doesn’t believe him and has an outbreak again. Next day she seems fine and the family decide to go to the fair and relax there. But when they were returning home, Nicole grabs the wheel of the car and tries to drive off the road and off a cliff to kill herself and Dick. Dick is horrified, but instead of solving the family problem and health problem of Nicole, he immediately departs for the psychiatric conference, just fleeing and leaving his unstable wife with kids. He needs time to sort out his feelings: he loves Rosemary and Nicole equally but feels very miserable because of the state of his family life. He doesn’t know what to do and how to combine his parts of private life together. When Dick is on the conference, his father passes away and Dick has to go to USA to attend the funeral and manage the papers. Everything gets even worse when Dick learns that Abe North was killed in the bar during his another depression episode.
This all is too much for Dick. He decides to have some time for himself and goes to Rome to relax. There he meets Rosemary and finally sleeps with her - just to break up with her and send her away after the night. Trying to make the breakup easier Dick uses the methods of Abe North: he gets drunk and starts a fight with a policeman. He is taken to prison and beaten to half-death there. The situation starts to look grim, but Baby Warren learns about his miserable situation and helps Dick escape. Dick returns home, now having a life debt to Baby.
The third book shows us that the situation didn’t improve with time. Dick is a heavy drinker now, completely addicted to alcohol. Now he has to sell his part of the clinic, because he receives too many complaints from the patients: Dick is constantly drunk and sometimes not too ethical towards the young female patients. He tries travelling with Nicole again, but finally they return to their home, achieving nothing. Nicole starts inviting Tommy Barban to their home more and more often and finally decides to have an affair with him. Surprisingly her mental state greatly improves after this decision: Tommy’s presence gives her the confidence and stability she wished so much.
Rosemary also starts to visit Dick and Nicole sees that her husband looks equally happy when with her. Finally Dick goes to travel with Rosemary, leaving Nicole and Tommy at home. When Dick returns home, he sees happy Nicole, who asks him if his relationship with Rosemary going well. Dick replies that it is over and this time forever. Tommy asks Dick out for a talk and says that he wants to be with Nicole, accusing Dick of mistreating her and ignoring her needs. Dick admits that Tommy is partially right and agrees to leave, spending the rest of the time until his departure with his children.
The novel ends, letting us know that Dick and Nicole managed to preserve good relationship, they keep in touch and the kids know that they still have a dad. Dick is now in America, starting everything anew and rebuilding his career as a psychiatrist. Nicole is happy with Tommy and hopes that now Dick feels good and free enough to achieve his goals.