An opera star's manager tries to stop her romance with a penniless singer.

At a small town May Day celebration, elderly Miss Morrison tries to console her young friend Kip, whose sweetheart Barbara has been offered a job on the operatic stage. Later Barbara goes for comfort to Miss Morrison, who reveals that years ago she was the internationally famous opera diva Marcia Mornay. Miss Morrison then relates her story: Marcia, a young American singer in Paris, is guided to success by famed voice teacher Nicolai, who introduces her at the court of Louis Napoleon. That night, Nicolai proposes to Marcia and she accepts, even though they both know that she is not in love with him. Later, feeling restless, Marcia takes a ride, and is stranded in the Latin Quarter when her driver's horse runs away. In a tavern, she meets American Paul Allison, who is also a singer, but not as ambitious as Marcia. Though they are attracted to each other, she at first refuses to see him again out of loyalty to Nicolai, but soon promises to lunch with him the next day. They enjoy their lunch together, but Marcia again says that they can no longer see each other and leaves. Paul then steals tickets to see her perform The Huguenots that evening, and after he is thrown out of his seat by the manager, he goes to her dressing room and only leaves when she promises to join him at St. Cloud for a May Day celebration. During the celebration, Paul tells her he loves her, but she says that she owes Nicolai too much and could never break a promise to him. They then part after vowing always to remember their day together. As the years pass, Marcia, who has married Nicolai, becomes the toast of the operatic world, but upon her triumphant return to America, she realizes that her life is hollow. Though faithful and devoted to Nicolai, her lack of passion for him has made them both unhappy. In New York, Nicolai arranges for Marcia to sing Czaritza , co-starring with Paul, who has become a baritone of some note, but who Nicolai does not realize is in love with Marcia. At rehearsal, they act at first as if they have never met before, but Nicolai begins to suspect the truth when Archipenco, Paul's singing teacher, talks about meeting Marcia in Paris many years before. Nicolai then recognizes Paul as the young man who left Marcia's dressing room after the performance of The Huguenots . On a brilliant opening night, Nicolai becomes jealous over the obvious emotion in Paul and Marcia's onstage love scenes, but doesn't know that they plan to run away together. Later, at their hotel, when Nicolai questions Marcia, she asks for her freedom, which he promises to give. Marcia soon discovers, however, that Nicolai has gone after Paul with a gun. At Paul's apartment, Nicolai shoots him just as Marcia arrives. Paul then dies in her arms, telling her that memories of their May Day together did last him all his life. At the conclusion of her story, Miss Morrison helps Barbara realize that she and Kip belong together. As she watches the young lovers embrace, Miss Morrison dies and is finally united with her own sweetheart in death.