The story of Florence Foster Jenkins, a New York heiress, who dreamed of becoming an opera singer, despite having a terrible singing voice.

Paris in the 1920s. Marguerite Dumont is a wealthy woman with a passion for music and the opera. For years, she has performed regularly for a circle of guests. But Marguerite sings tragically out of tune and no one has ever told her. Her husband and her close friends have always encouraged her in her illusions. Things become very complicated the day she gets it into her head to perform in front of a genuine public, at the Opera.

Florence Foster Jenkins is known as "the worst singer of all times" and yet she is a cult figure whose recordings still outsell many contemporary singers. Opera superstar Joyce DiDonato interprets the flamboyant "queen of dissonance". The involvement of the celebrated virtuoso makes it possible to contrast two different musical perspectives and gives viewers a vivid impression of the film's key conflict between inner delusion and external reality.