Queen Elizabeth I is toying with a marriage proposal from a French prince when her court asks what she intends to do about her cousin Mary Stuart, former Queen of France and then of Scotland, who has been condemned to death for conspiring against Elizabeth. Talbot, who hosted Mary Stuart during the first part of her long house arrest in England, encourages Elizabeth to be lenient, but Elizabeth’s trusted advisor Cecil fears that Mary is a threat to Elizabeth’s throne. Talbot then asks Leicester, Elizabeth’s favorite, to intercede on behalf of Mary, whom Talbot and Leicester both love. In the duet “Era d’amor l’immagine,” Leicester begs Elizabeth to meet Mary face to face. Reluctantly, she agrees.
Accompanied by her attendant, Hannah, Mary enjoys the park of the castle where she is imprisoned and recalls her happy childhood in France (aria: “O nube che lieve”). Leicester informs Mary that Queen Elizabeth has agreed to visit her, and warns her to be humble and submissive before her cousin. Using the royal hunt as an excuse, Elizabeth appears; all are nervous (sextet: “È sempre la stessa”). Although Mary begs Elizabeth to have mercy on her, Elizabeth goads and provokes Mary, who eventually explodes, calling Elizabeth illegitimate to her face.
Cecil urges Elizabeth to sign Mary’s death sentence, claiming that so long as Mary lives, Elizabeth will never be safe from attempted coups. But Elizabeth is not ready to shed royal blood. Leicester’s support for Mary tips the scales: Elizabeth signs Mary’s death sentence and commands Leicester to prove his loyalty by seeing that the execution is carried out.
Cecil informs Mary that she will be executed the next day; she refuses his offer of a Protestant minister. But she opens her heart to Talbot in the duet “Quando di luce rosea,” confessing her sins and preparing to meet her maker.
The next morning, in the great hall of Fotheringhay, Mary’s friends pray with her. She forgives Elizabeth, encourages Leicester not to shed further blood by attempting to avenge her, and goes in strength to a martyr’s death.
The following historical figures are prominently mentioned in the opera:
Anne Boleyn. Elizabeth’s mother. In order to wed her, Henry VIII broke with the Catholic Church and established the Church of England. Later, he claimed she was a witch, had her beheaded, and proclaimed Elizabeth illegitimate.
David Rizzio. An Italian musician and courtier to Mary Stuart in Scotland, assassinated by rivals including Mary’s second husband.
Henry Stuart, Lord Darnley. Mary Stuart’s second husband died in mysterious circumstances. Mary was accused of taking a lover who then assassinated Darnley.
Anthony Babington. A young Catholic Englishman who attempted to rescue Mary Stuart from house arrest and set her on Elizabeth’s throne. He failed; was hanged, drawn, and quartered; and Mary, who knew of his plot, was convicted of treason.