Roberto Devereux, the second Earl of Essex, is awaiting trial after having agreed to a ceasefire with rebels. Meanwhile, Sara, Duchess of Nottingham, is in love with Roberto and learns from Queen Elisabeth herself that she too is in love with him. Elisabeth plans to pardon him of the charge of treason if she can be sure of his loyalty, expecting the Earl to accept her love. She tells him that the ring she once gave him will always be a pledge of his safety but she turns against him upon realizing that he loves another.