Notorious playboy Nickie Ferrante makes worldwide headlines when he becomes engaged to Lois Clark, one of the richest heiresses in America. While sailing from France to New York to meet his intended, Nickie is intrigued when he sees fellow passenger Terry McKay carrying his misplaced cigarette case. After Terry returns the case, Nickie tries to flatter her, prompting her to comment sarcastically on his reputation. When Nickie follows Terry to her room, she points to the photograph of Kenneth, her fiancé, nestled on her nightstand, and although Terry steadfastly resists Nickie's charm, she accepts his dinner invitation. Over dinner, the tart-tongued Terry banters with Nickie. The next day, as each receives a message from his or her sweetheart, Terry tells Nickie that she worked as a nightclub singer until meeting the wealthy Kenneth, who has been schooling her on how to be the perfect cultured wife. Concerned that their fellow passengers may gossip about their budding friendship, Terry insists that she and Nickie go their separate ways. That night, when they are seated back to back at different dining tables, the room breaks out into laughter at their charade. During a chance meeting in the swimming pool the next morning, Nickie invites Terry to meet his grandmother when the ship docks at Madeira. Terry is certain that he is taking her to visit another one of his conquests until she meets the gracious aging woman who inhabits the serene villa on the hill. There, Terry and Nickie kneel in the chapel together, and Nickie is profoundly moved when Terry solemnly bows her head in prayer. Afterward, during a tête-à-tête with Nickie's grandmother, Terry learns that Nickie is a talented artist, but that his restlessness has prevented him from developing his ability. Grandmother then confides that she hopes Terry may provide the anchor to Nickie's rootlessness. Later, as Grandmother plays a tune on the piano, Terry accompanies her in song. Their idyll ends when the ship's horn summons them back, and after Grandmother tearfully bids Nickie goodbye, she promises to send Terry her beautiful white lace shawl one day. That night aboard the ship, Terry thanks Nickie for a memorable day, and after they kiss, Nickie comments that they have changed course. On the evening before docking in New York, Terry confesses that she no longer loves Kenneth. Realizing that they have both finally found happiness, Nickie proposes and asks Terry to wait for him six months so that he can prove himself worthy of supporting her. Terry promises to give him her answer in the morning. The next day, as they sail into the New York harbor, Terry makes a date to meet Nickie in six months, on July 1, at 5 o'clock in the afternoon, and Nickie suggests that they reunite at the Empire State Building, the nearest thing to heaven in New York. When the ship docks, Nickie and Terry half-heartedly greet their intendeds, and as Kenneth hugs Terry with his back to Nickie, Nickie pauses and tenderly places a kiss on Terry's hand. At Lois' estate, Nickie is about to break his engagement when a television reporter arrives to interview the couple whose "romance has captured the imagination of the whole world." Kenneth and Terry watch the interview, and when Terry reacts emotionally to Nickie's statement that he plans to marry in six months, Kenneth realizes that she has fallen in love with him. Three months of hard work later, Nickie takes a series of paintings to Courbet, the art dealer. Although Courbet advises Nickie to trade on his notoriety, Nickie insists on painting under a pseudonym. Terry, meanwhile, has resumed her singing career in Boston. Desperate for money, Nickie takes a job as a billboard painter until he finally sells his first canvas. At the end of six months, Terry flies to New York. In anticipation of her wedding, she stops at her favorite dress shop to buy an "irresistible" frock. When the clerk notifies Kenneth that Terry is there, he hurries to meet her. Protesting that she is late, Terry rushes out the door. After hailing a cab to the Empire State Building, Terry jumps out at her destination and with her eyes focused skyward, she is struck by an oncoming car. High atop the Empire State Building, meanwhile, Nickie anxiously awaits Terry's arrival, impervious to the ambulance sirens below. As midnight approaches, a torrential rainstorm breaks over the city and Nickie, despondent, ends his vigil. Meanwhile, in a nearby hospital, an incoherent Terry calls for Nickie, and her doctor informs Kenneth that she may never walk again. Stubbornly refusing to contact Nickie until she is able to walk, the convalescing Terry takes a job teaching music to orphaned children. Upon his grandmother's death, Nickie makes a final pilgrimage to her villa and wistfully recalls the blissful night he spent there with Terry. At Christmastime, Nickie returns to New York for a showing of his work, and is invited by Lois to attend the theater. After the performance, Nickie is stunned to see Terry seated on the aisle with Kenneth. On Christmas Eve, Nickie, unaware of Terry's condition, appears at her door and finds her reclining on the couch. After bitterly reproaching her for failing to keep their rendezvous, Nickie presents her with his grandmother's shawl. As Terry drapes the shawl across her shoulders, Nickie sardonically remarks that he once painted her wearing that shawl. He continues that Courbet told him that a young, crippled woman admired the painting with such fervor that he instructed the art dealer to give it to her. Finally comprehending that Terry was that woman, Nickie flings open her bedroom door and, seeing the painting, is confronted with the painful truth of her condition. After he tearfully embraces her, Terry declares that if he can paint, she can walk.