Louise Durant Elizabeth Taylor is a debutante who announces to her haughty father, Nicholas Durant Louis Calhern, that she plans to leave their luxurious home for Zürich with her lover, the aspiring violinist Paul Bronte Vittorio Gassman. He disapproves, insisting he needs her to host a VIP luncheon and noting she lacks the discipline to study piano at the conservatory. She fires back with defiance, muttering that he has never stopped her before, and he concedes only with a sharp warning about the consequences of defying him.
The couple speeds off in a convertible toward Zürich, Bronte joking about how impractical the plan is since he must work. In Zürich, they carry Durant’s bags to a stylish furnished flat, where Bronte learns from a matron Celia Lovsky that an American lodger, James Guest John Ericson, has just moved into the attic. When Guest appears, Bronte tries to claim the room on seniority, but Guest stands his ground. He is immediately drawn to Durant, even though Bronte makes it clear she is off-limits.
Durant heads to the conservatory to audition. While she waits, she is captivated by the piano student before her, only to discover it is Guest. The audition proceeds under the watchful eye of the professor who oversees it, and Bronte joins for his own turn. The two men vie for Durant’s affection and approval, but she remains focused on the music while Bronte prioritizes his practice and career.
Bronte soon learns that he is scheduled to perform with the Zürich Symphony in three weeks. He bluntly tells Durant that he will have little time for her until the concert, a revelation that stings as a grand piano arrives for Durant. Guest and Durant test out the new instrument together, forming a growing friendship as the distance between Durant and Bronte widens.
Durant’s father visits Zürich and meets Bronte, a troubling encounter for Durant. The elder Durant’s disdain is palpable, and when he is invited to Bronte’s Tchaikovsky concert, he refuses, quipping that he has already heard Tchaikovsky. He also voices a prediction about the couple’s doomed future, noting Bronte’s arrogance and the impossibility of confining him. Durant confronts him with a fierce defense of her partner, while the father hints at the tension between Bronte’s freedom and Durant’s need for security.
Bronte’s solo at the Symphony is a triumph. Durant watches from backstage, trying to gain his attention, but he is absorbed in the music and in deals with music agents. He pays her no mind, and when a crowd gathers around him, she notices him kiss another woman in a moment of shared ecstasy. After the performance, Bronte outlines his touring plans, including a Rome finale, and bluntly states that Durant cannot accompany him because she would be a distraction. The couple quarrels, and Durant is left alone with the sense that his music will always come first.
The next day, Durant discovers Bronte has left for the tour with a different woman. Heartbroken, she attempts suicide with pills, but Guest intervenes, saving her life. He becomes her caretaker, and her father reconsiders his stance, giving his blessing to Durant’s choice to heal and move forward. Durant decides to leave Zürich with Guest, moving to Paris, where she marries him in a bid to mend her heartbreak and rebuild her life.
In Paris, Bronte crosses paths with Durant again, and the two acknowledge that they have not fallen out of love. Meanwhile, Guest struggles with his own ambitions, spending Durant’s money on liquor and feeling overlooked in the pursuit of affection he cannot win. Bronte is dismayed to see Durant’s long-dormant talent slowly eroding under the weight of her new life, while Durant confronts the reality that her decision to marry Guest was not enough to quiet the ache he inspires.
Durant eventually returns with Guest to Zürich, dedicating herself to supporting his musical development. Guest earns a solo at the Symphony, a moment that tests their fragile arrangement. He worries about Durant’s support; she promises him that his talent comes from his hard work alone and hints at leaving with Bronte after the performance. Guest is crushed by this confession, his hopes weighed down by the sense that his relationship with Durant may not endure.
At the concert, Guest endures a storm of nerves and longing as he watches the empty chair reserved for Durant. The performance is a success, and afterward he faces the heartbreak of her absence and the pain of his own loneliness. When Durant finally arrives, she reveals that she stayed to witness the entire performance, and the two share a tearful, decisive embrace as they acknowledge their enduring connection: they are pulled together as lovers once more, even as the music carries them forward.
