It is a January evening in 1870s New York City and the fashionable are attending the opera. As young Newland Archer, lawyer and man about town, gazes up at his soon-to-be fiancé, May Welland, in the Mingott-family opera box, he is disconcerted by the arrival of May's cousin, the Countess Ellen Olenska, who has left her profligate but wealthy Polish husband. To discourage gossip, Newland decides to announce his and May's engagement at the Beaufort's ball that night.
All of old New York is at the ball, gossiping about the Countess. Later, when the family plans a dinner to introduce her to society, no one accepts. Without delay, the Mingott family enlist the help of ancient social sages, Henry and Louisa van der Luyden, to shore up support by inviting old New York to a dinner it cannot refuse. In this way they introduce the exotic Countess, and she finds New York society charmingly narrow and provincial compared to Paris. The next day Newland visits the Countess' small house in a Bohemian section of town. He finds her drawing room exotic and her friendship with shady financier Julius Beaufort unsettling. But he senses her loneliness and, despite some misgivings, sends her yellow roses.
The Mingotts enlist Newland's boss, Mr. Letterblair, to ask Newland to dissuade the Countess from seeking a divorce. When Newland speaks with Ellen — a passionate and exotic woman, unlike his quiet, innocent May — he finds himself falling in love with her, despite his engagement. Worried by temptation, Newland flees to Florida where May's family is vacationing and asks May to move the wedding date up. Startled, May tells him that if there is "someone else," he may have his freedom. Touched by her selflessness, Newland returns to New York. As he confesses his love to Ellen, a telegram arrives from May, saying that they can be married in a month. Newland knows his duty.
