Psychiatrist Huntington "Hunt" Brailey recalls a chance meeting that began the strangest days of his life: In the early spring of 1903, Hunt meets Clarissa "Cissie" Bedereaux when the eastbound train on which they are traveling is assailed by a violent storm. When Hunt calms the frightened Cissie, she invites him to join her for lunch the following day. At lunch, Cissie tells Hunt that she is returning home to see her brother Nick after spending five years in a sanitarium for her heart condition. After confiding that she is writing a manuscript about her volatile brother and his beautiful young wife Allida, Cissie announces that she has decided to live on her own and asks Hunt to take her suitcases to his hotel and reserve a room for her. In New York that evening, Hunt joins his friends, Clag Claghorn and Elaine, for dinner. At the restaurant, he overhears artist John Maitland describing the sudden death of Cissie Bedereaux. When Hunt exhibits an interest in the Bedereaux family, Clag sends his friend to the museum to view Maitland's portrait of Allida and invites him to tea at the family mansion. Upon returning to his hotel, Hunt sends Cissie's luggage to the Bedereaux mansion on Murray Hill. Unknown to Hunt, the hotel maid has accidentally switched his briefcase with Cissie's, which now sits in his closet. The next day, Hunt is captivated by Allida's portrait and accepts Clag's invitation. Upon meeting the overwrought Allida, Hunt is enchanted by her beauty and tells her that he would have painted her standing in a field of daisies. Soon after, Nick visits Hunt at his office and states that he thinks his wife is insane. As proof, Nick tells Hunt that Allida sends herself daisies and is instilling night terrors in their young son. Intrigued, Hunt accepts Nick's request to observe Allida. On his way home that day, Hunt notices a man following him, and when he arrives at his hotel, he finds Cissie's briefcase in the closet and discovers her diaries. Her manuscript relates the story of Nick: After their mother died while giving birth to Nick, their father blamed the infant for her death and one year later, committed suicide. Cissie reared Nick, who later became infatuated by the much younger Allida when he encountered her standing in a field of daisies. Nick invited Allida to accompany him and Cissie to Europe, and two years later, after molding her into a sophisticated woman, he married her. In New York, Nick gives Allida a birthday party. Writer Alec Gregory, who is in love with Allida, presents her with a bouquet of daisies and later recites a love poem that he has written for her. Nick, jealous, overhears Alec's confession of love, and after the party, the two men argue. Hunt's study of Cissie's narrative is cut short when Allida phones and asks him to follow Nick to their son's room when he comes to their house for dinner the next evening. Sensing danger, Hunt goes to visit Clag, but before leaving his room, he hides Cissie's case. When Hunt tells Clag that he finds Nick sinister and thinks that someone is following him, Clag discounts his friend's fears. Hunt's suspicions are confirmed, however, when he returns to his hotel room and discovers that Cissie's case is missing. At dinner the next night, Hunt is mystified to learn that the Bedereauxs' young son is named Alec. At the dinner table, when Nick criticizes Allida for ordering daisies, she protests that she ordered roses. When Nick is called away from the table to comfort the hysterical Alec, Hunt follows him and finds a discarded bouquet of roses in the hallway. While standing in Alec's doorway, Hunt listens as Nick terrorizes his son with stories of bad witches and tells him that Allida is one of them. After dinner, Hunt excuses himself to visit a patient, and after Nick leaves for his club, Hunt calls Allida and asks her to meet him at a restaurant. When Hunt questions her about Alec Gregory, Allida tells him that Alec was run over and killed on the night of her birthday party while walking with Nick and that Nick insisted on naming their son after Alec. Concerned for Allida's safety, Hunt calls Clag at the club to make sure that Nick is still there. After a drunken Clag repeats their conversation aloud, Hunt sends Allida home and writes Clag a letter detailing his suspicions about Nick murdering Alec and Cissie. The next day, Allida visits Hunt at his office and tells him that Nick has boarded a ship bound for Boston. Soon after, Hunt receives a note from Nick, informing him that he is planning to commit suicide by jumping overboard and challenges the doctor to stop him. In a moral quandary, Hunt escorts Allida home, and when she hears Alec crying, she goes upstairs to his room. Hunt is about to call Clag when Nick, disguised in a butler's uniform and carrying a gun, emerges from the shadows. After calmly informing Hunt that he killed Cissie because she realized that he was trying to drive Allida mad, Nick announces that he has adjusted the gas stove in the nursery to explode and kill Allida and Alec. By knocking over a table, Hunt distracts Nick and knocks him unconscious, then runs upstairs to save Allida and Alec. Regaining consciousness, Nick races up the stairs, and as the two men struggle, the house explodes. Seeing the fire trucks headed for Murray Hill, Clag follows and learns that a man was killed in the explosion. Some time later, in a country house surrounded by fields of daisies, Hunt reassures Alec with stories of good witches. When the district attorney visits Allida to inform her that the dead butler's dental records match those of her husband and concludes that Nick was criminally insane, she asks him to consider how the information would affect her son and he decides to drop the case. Allida then walks outside to join Alec and Hunt in the fields.