This film tells the story of one of the most magic moments of music. The beginning of 1964 held a great surprise for the music world: Maria Callas returns to the opera stage as prima donna. Her "Tosca" at the Royal Opera House becomes a sensation. Not even the Beatles received more press coverage. All this, for an artist whose glorious career was said to be over, with the singer herself passing over to legend. It is no longer her performances, but her scandals that are dominating the headlines. Unlucky in love with her billionaire boyfriend Aristotle Onassis, Maria Callas wants to show them all that the title of "Primadonna assoluta" is still rightfully hers. On condition that famed stage director Franco Zeffirelli takes on the production, the exceptional vocalist is prepared to take on the role of Tosca. The film tells the story of the event from today´s perspective and features interviews with Antonio Pappano, Rolando Villazon, Rufus Wainwright, Thomas Hampson, Anna Prohaska Wolfgang Joop, Jurgen Kesting, Brian McMaster, and Kristine Opolais. As a bonus the performance of Tosca´s second act is included. It is one of the most dramatic acts in opera history. The film recording is one of the few opportunities to see Maria Callas on stage and witness her emotional dramatics and vocal competence.