Paris, 1730. Backstage at the Comédie-Française, the director Michonnet and the company prepare for performance, in which both Adriana Lecouvreur and her rival, Mademoiselle Duclos, will appear. The Prince of Bouillon and the Abbé de Chazeuil enter, looking for Duclos, who is the prince’s mistress. They encounter Adriana and compliment her, but she says that she is merely the servant of the creative spirit (“Io son l’umile ancella”). The Prince hears that Duclos is writing a letter to someone and arranges to have it intercepted. Left alone with Adriana, Michonnet confesses his love to her, only to be told that she is in love with Maurizio, whom she believes to be an officer in the service of the Count of Saxony. Maurizio enters, declaring his love for Adriana (“La dolcissima effigie”), and the two arrange to meet after the performance. Adriana gives him a bouquet of violets as a pledge of her love. During the performance, the prince intercepts the letter from Duclos, in which she asks for a meeting with Maurizio, who is in fact the Count of Saxony himself. He is to meet her later that evening at the villa where the prince has installed her. Determined to expose his seemingly unfaithful mistress, the prince arranges a party at the villa for this same night. Unknown to him, Duclos has written the letter on behalf of the Princess of Bouillon who was having an affair with Maurizio. Maurizio, receiving the letter, decides to meet the princess who has helped him pursue his political ambitions. He sends a note to Adriana to cancel their appointment. Adriana is upset, but when the prince invites her to the party and tells her that the Prince of Saxony will be one of the guests, she accepts in the hope of furthering her lover’s career.
The princess anxiously awaits Maurizio at the villa (“Acerba voluttà”). When he appears she notices the violets and immediately suspects another woman but he quickly claims they are a gift for her. Grateful for her help at court, he reluctantly admits that he no longer loves her (“L’anima ho stanca”). The princess hides when her husband and the Abbé suddenly arrive, congratulating Maurizio on his latest conquest, who they think is Duclos. Adriana appears. She is astounded to learn that the Count of Saxony is Maurizio himself but forgives his deception. When Michonnet enters looking for Duclos, Adriana assumes that Maurizio has come to the villa for a secret rendezvous with her. He assures her that the woman hiding next door is not Duclos. His meeting with her, he says, was purely political and they must arrange for her escape. Trusting him, Adriana agrees. In the ensuing confusion, neither Adriana nor the princess recognize each other, but by the few words that are spoken each woman realizes that the other is in love with Maurizio. Adriana is determined to discover the identity of her rival, but the princess escapes, dropping a bracelet that Michonnet picks up and hands to Adriana.
As preparations are under way for a party at her palace, the princess wonders who her rival might be. Guests arrive, among them Michonnet and Adriana. The princess recognizes Adriana’s voice as that of the woman who helped her escape. Her suspicions are confirmed when she pretends Maurizio has been wounded in a duel and Adriana almost faints. She recovers quickly, however, when Maurizio enters uninjured and entertains the guests with tales of his military exploits (“Il russo Mencikoff”). During the performance of a ballet, the princess and Adriana confront each other, in growing recognition that they are rivals. The princess mentions the violets, and Adriana in turn produces the bracelet, which the prince identifies as his wife’s. To distract attention, the princess suggests that Adriana should recite a monologue. Adriana chooses a passage from Racine’s Phèdre, in which the heroine denounces sinners and adulterous women, and aims her performance directly at the princess. The princess is determined to have her revenge.
Adriana has retired from the stage, devastated by the loss of Maurizio. Members of her theater company visit her on her birthday, bringing presents and trying to persuade her to return. Adriana is especially moved by Michonnet’s gift: the jewellery she had once pawned to secure Maurizio’s release from prison. A box is delivered, labeled “from Maurizio.” When Adriana opens it, she finds the faded bouquet of violets she had once given him and understands it as a sign that their love is at an end (“Poveri fiori”). She kisses the flowers, then throws them into the fire. Moments later, Maurizio arrives, summoned by Michonnet. He apologizes and asks Adriana to marry him. She joyfully accepts but suddenly turns pale. Michonnet and Maurizio realize that the violets were sent by the princess and had been poisoned by her. Adriana dies in Maurizio’s arms (“Ecco la luce”).