A schoolteacher is surprised to find love on a Venetian vacation.

American Jane Hudson, a middle-aged, unwed secretary, is thrilled upon her arrival in Venice, which marks her first vacation abroad. During the water bus ride to her hotel, the Pensione Fiorini, Jane meets two other Americans, Lloyd and Edith McIlhenny, who are engaged in a whirlwind European tour. Jane films their journey with her 16mm camera and revels in the unfamiliar sights and sounds of Italy. At the pensione , Jane is greeted by Signora Fiorini, a sensual widow who turned her home into a tourist boardinghouse after World War II. The gregarious Jane also meets Eddie Yaeger, a young American painter who is studying art in Italy with his wife Phyl. When the signora shows Jane her room, Jane confides that during the trip, she met a girl who was coming to Venice to find something, a "magical, mystical miracle," that she had been missing her whole life. Signora Fiorini realizes that Jane is speaking of herself, and that she hopes to find romance. That evening, the other guests have their own plans and leave, although Jane tries to persuade them to stay for another drink. Before she also leaves, Signora Fiorini tells Jane that miracles can happen, but one must give a little push to help them along. Setting out alone, Jane runs across a street urchin, Mauro, who sells her some photographs. Jane then walks to the famed Piazza San Marco, although her initial awe wears off as she gazes sadly at the strolling couples. A lone Italian man, sitting behind her, is bemused by Jane's attempts to cheer herself up by taking pictures with her camera, but when she sees him watching her, she hurriedly leaves. The next day, Mauro takes Jane on a tour of the city, after which she goes shopping. Enthralled by the sight of a red, glass goblet in the window of an antiques store, Jane enters and is embarrassed to find that the owner, Renato De Rossi, is the man from the previous evening. Renato, who is pleased to see Jane again, assures her that the goblet is 18th century, and when she readily agrees to his asking price, instructs her in the Italian art of bargaining. Hoping to see her again, Renato offers to search for a mate for the goblet and asks for the name of her pensione . That evening, Jane goes to the same café at the piazza and arranges her table so that she can save a seat for Renato. When Renato walks by, however, he assumes that she already has a companion, and Jane is crushed that he leaves. The following morning, Jane is again walking with Mauro, who, upon seeing her eagerness to visit the antiques store, irritates her with a comment about Venice being "different for ladies." Disappointed that Renato is not at the shop, Jane is brusque to Mauro, who consequently does not warn her when she is shooting some film and, not seeing where she is going, falls backward into a canal. A crowd gathers as Jane swims to the steps and, soaking wet, retreats to the pensione . That evening, Renato comes by to check on Jane, who is disturbed by his frank declaration that they have been attracted to each other from their first meeting. Jane protests, stating that he is moving too quickly for her, but Renato insists that they are "simpatico" and should not waste this opportunity for happiness. Jane is about to agree to dine with Renato when the McIlhennys return from shopping, and Edith shows her a set of new, red goblets she bought. Thinking that Renato swindled her, Jane is furious, but Renato insists that her goblet is an antique, and also shows that she paid less than Edith did for her goblets. Despite Jane's trepidation, Renato persuades her to attend a concert with him at the piazza. There, Jane is blissfully content with the grand music, stunning architecture and her charming companion. A flower seller walks by, and Renato is surprised when Jane chooses a gardenia instead of a more dramatic orchid or rose. Jane explains that in her youth, she wanted to wear a gardenia corsage to a ball, but her escort could not afford the expensive flowers. The couple are upset when Jane loses her gardenia in a canal, but continue their romantic evening, walking hand-in-hand to her pensione . Although she is at first frightened by Renato's kiss, Jane kisses him back passionately and whispers, "I love you," before dashing away. The next day, Jane splurges on beauty treatments and new clothes in anticipation of her date that evening with Renato. While she waits at the piazza, however, Renato's assistant, Vito, arrives and innocently reveals that he is Renato's son. Aghast to learn that Renato has several children and is married, Jane runs off to a bar. There, Jane finds a distraught Phyl drinking away her sorrows over her troubled marriage. Jane tries to comfort her, telling her that two is the best number, but when she returns to the pensione , Jane discovers that Eddie is having an affair with Signora Fiorini. Shocked, Jane takes out her anger on Mauro, who summoned a gondola for Eddie and Signora Fiorini. Renato arrives and stops her from shaking the confused boy, then tells her that what the signora and Eddie do is their business, not hers. Renato then reveals that he is married but separated, and confesses that he did not tell her for fear that she would end their relationship. Renato scolds Jane for being childish and wanting too much instead of taking what she can have, and Jane agrees to dine with him. After spending a delightful evening together, the couple return to Renato's apartment and Jane's dreams of romance are fulfilled. Jane and Renato then spend a happy idyll on the colorful island of Burano. Upon their return, however, Jane secretly makes plans to return to America. When Jane asks Renato to join her for a walk, she tells him that she is leaving in two hours because she cannot bear for their affair to continue until it ends in pain for them both, due to his marriage. Renato begs her to stay, but Jane assures him that it is always best to leave a party before the end. Although she tells Renato that she does not want him to see her off at the train station, Jane waits anxiously for him. As the train begins to move, Jane is in despair, but lights up when she sees Renato running toward her. Renato tries to pass a present to her but cannot keep up with the train as it gathers speed, and so shows her that he bought her another gardenia. Blowing a kiss of thanks, Jane then waves until he is out of sight.