In the heart of Europe, a young American named Winterbourne finds himself caught in a web of social intrigue and personal discovery. His chance encounter with Daisy Miller, a fellow American, leads him on a journey through cultural contrasts and personal realizations. As he navigates the traditional European society with his newfound acquaintance, Winterbourne comes to terms with his own feelings and the societal expectations that surround him.

The Encounter at Vevey

Winterbourne, a long-time American expatriate in Europe, often frequents the picturesque town of Vevey, known for its serene beauty. While relaxing outside his aunt Mrs. Costello's favored hotel, he notices a captivating young woman. She is Daisy Miller, the sister of the American boy, Randolph, with whom Winterbourne had been chatting. The Miller family, originally from Schenectady, is on a European tour and plans to travel to Italy next, although young Randolph insists he wants to return home. Daisy expresses her desire to visit the historic Castle of Chillon, and Winterbourne, familiar with the area, eagerly volunteers to accompany her.

Daisy's Impact and Mrs. Costello's Disapproval

Intrigued by Daisy, Winterbourne asks Mrs. Costello to meet her. However, his aunt declines, dismissing the Millers as "common." Despite the cold reception from Mrs. Costello, Winterbourne and Daisy plan a nighttime boat ride on the lake, only for Daisy to change her mind at the last minute, much to the relief of Eugenio, their protective traveling companion. A subsequent trip to the Castle of Chillon further solidifies Mrs. Costello's unfavorable opinion, as she labels Daisy unsophisticated and lacking in refinement.

Reunion in Rome

Winterbourne's journey continues to Rome, where he reconnects with Daisy and her family at the home of Mrs. Walker, an acquaintance from Geneva. Daisy playfully admonishes Winterbourne for not visiting sooner. During the visit, Daisy requests to bring an Italian acquaintance, Mr. Giovanelli, to an upcoming party hosted by Mrs. Walker, who reluctantly agrees. Daisy's casual plan to stroll through Rome with Giovanelli shocks Mrs. Walker, who views such behavior as scandalous for an unmarried woman. Daisy cleverly suggests that Winterbourne joins them to quell any potential gossip.

The Walk and Mrs. Walker's Dismay

As Winterbourne, Daisy, and Giovanelli walk through Rome, Mrs. Walker's carriage pulls up beside them. She implores Winterbourne to persuade Daisy to end her walk, fearing that her actions will tarnish her reputation. Mrs. Walker issues a stern ultimatum to Winterbourne, threatening to sever ties if he fails to intervene. Despite these pressures, Daisy remains steadfast, choosing to continue her walk with Giovanelli.

Social Isolation and Misunderstanding

Determined to exact social retribution, Mrs. Walker plans to ostracize Daisy at her party. When the evening arrives, Daisy finally appears with Giovanelli, much to Mrs. Walker’s dismay. In a fleeting moment of civility, Mrs. Walker greets them, only to later turn her back on Daisy when she bids goodnight. The repercussions are swift and severe; social circles close their doors to Daisy and Giovanelli. Winterbourne occasionally crosses paths with Daisy, but she is invariably accompanied by the Italian, fueling rumors of their supposed affair. When questioned by Winterbourne, Daisy denies any engagement to Giovanelli.

Moonlit Ruins and Tragic Consequences

Amidst the backdrop of Rome's historic ruins, Daisy's determination leads her to the Colosseum under the moonlight, disregarding warnings of malarial fever. Winterbourne, upon finding them there, chastises Giovanelli for his recklessness, though he learns it was Daisy's insistence that brought them to the ancient site. Tragically, Daisy falls ill shortly after this nocturnal adventure. As her health deteriorates, she sends a poignant message to Winterbourne, affirming she was never engaged to Giovanelli. Her illness proves fatal, and she passes away within a week.

Reflections at the Grave

Standing by Daisy's grave in Rome's Protestant cemetery, Giovanelli confides in Winterbourne that Daisy would never have married him, even if she had survived. This revelation prompts Winterbourne to confront his own emotions, realizing too late that he had loved Daisy. He regrets not recognizing his feelings sooner and blames his extended time in Europe for clouding his perception of American freedoms and complexities. In her death, Daisy leaves a lasting impact on Winterbourne, shedding light on the nuances of identity and cultural expectations.