Act I
August 1572. Paris is abuzz with the royal wedding festivities. The union of the Catholic Marguerite de Valois and the Huguenot Henry of Navarre is poised to quell the religious strife between the two Christian denominations, heralding a much-anticipated era of peace in France. Count de Nevers, a Catholic, hosts guests at his castle and informs them of another expected guest – the young nobleman Raoul de Nangis, whom he recently befriended in Paris. Raoul, a Huguenot, is anticipated to receive a warm reception from Nevers' Catholic friends, in light of the royal decree proclaiming peace between Catholics and Huguenots.
Raoul soon makes his entrance, and wine is served. Noticing the young man's pensive demeanor, the castle's lord is eager to uncover his heartfelt secret. Yielding to persuasion, Raoul recounts how, a few days prior, during a stroll, he rescued a beautiful unknown maiden from the bothersome advances of a drunken group of students. Smitten by the young stranger, he fell in love with her.
As Raoul shares his tale, his loyal servant and mentor, the old Huguenot soldier Marcel, appears. He watches with disdain as his master mingles with the detested Catholics. Attempting to reason with Raoul and take him away, Marcel sings a Lutheran hymn.
Nevers requests Marcel to sing something different. Marcel then recalls a militant song about the hatred for papists, sung by Huguenots defending the fortress of La Rochelle. Nevers' servant announces the arrival of an unknown lady. Nevers steps out to meet the visitor. To his astonishment and horror, Raoul recognizes her as the maiden he had saved. He concludes that she must be Nevers' mistress. Raoul is in despair: could she, who seemed so "innocent, pure, and sweet," bestow her love on another?
Nevers returns, disheartened: his engagement has been annulled. The guests laud Nevers' success with women. Page Urbain arrives with a letter addressed to Raoul, setting a blindfolded rendezvous. Baffled, Raoul shows the letter to Nevers, who immediately recognizes the handwriting and crest of Marguerite of Navarre, King Charles IX's sister. All but the young Hugueno.
Act II
The magnificent garden of the Château de Chenonceau in Touraine serves as the setting. Here, in this earthly paradise, shielded from all troubles, Marguerite de Navarre spends joyful hours with her court ladies and page. Valentina, her lady-in-waiting, arrives to announce she has successfully annulled her engagement with Count de Nevers, having traveled to his castle for this purpose. Aware of Valentina's feelings, Marguerite promises to assist her in marrying Raoul. Page Urbain reports the young man's arrival. He is led in blindfolded. Marguerite commands everyone to leave and allows the guest to remove his blindfold. Struck by the beauty of the stranger, he passionately admires her. Hoping to forget Valentina in this new infatuation and unaware he is speaking to the queen, Raoul declares his love and admiration. Marguerite curtails the overly ardent admirer.
Catholic nobles, led by Nevers and Count de Saint-Bris – Valentina's father and the leader of the Catholic nobility, arrive, soon followed by the Huguenots, including Marcel. Addressing both conflicting parties, Marguerite expresses her hope that by marrying the King of Navarre, she can end the disputes between Catholics and Protestants. All vow to uphold the royal will and maintain peace.
Saint-Bris, affirming his willingness to reconcile with the Huguenots, consents to marry his daughter to Raoul de Nangis. He presents Valentina. Recognizing the lady who visited Nevers in her, Raoul feels insulted and rejects such a bride. The queen dismissively sends the young man away. Nevers and Saint-Bris are consumed with a thirst for revenge.
Act III
The Parisian Place des Prêcheurs is bustling with citizens anticipating the festivities. A troop of Huguenot soldiers led by Bois-Rosé arrives, singing the war song "Rataplan" about Admiral de Coligny. Their singing is interrupted by a wedding procession: Nevers is leading Valentina to the altar. Marcel addresses Saint-Bris, but the Catholics forbid the old Huguenot from speaking with the bride's father. A skirmish erupts, joined by the Huguenot soldiers. Gypsies arrive at the square, temporarily quelling the conflict.
The wedding ceremony concludes. Valentina remains in the church for solitary prayer, while Nevers leaves to fetch his friends. Saint-Bris exits the church and receives a letter from Marcel, challenging the count to a duel. Saint-Bris arranges with his friend Morever to attend the duel and assist in killing Raoul. They go to discuss the plan in the church, where Valentina is praying at that time.
As the curfew approaches, the square empties. Valentina exits the church, distressed: she has inadvertently overheard her father's conversation with Morever. How can she save Raoul from the assassins?! Marcel is tormented by the same question. Valentina begs the old servant to find his master and warn him of the impending danger. But Marcel doesn't leave in time: Raoul has already arrived at the square.
The duel begins, threatening to end in foul murder. Marcel comes to the rescue, calling the nearby Huguenot soldiers. Saint-Bris, in turn, summons the Catholic students. A fierce fight ensues. Only the appearance of the queen with her entourage compels the foes to lower their weapons. Marguerite is infuriated by the breach of the oath, but Marcel reveals the duel was intended as an assassination of Raoul. He presents the lady who told him about the plot. Saint-Bris recognizes her as his daughter. Raoul is bewildered, not expecting Valentina to be his savior. The queen then reveals the truth: Valentina visited Nevers to break off the engagement, making it possible to marry Raoul. Saint-Bris spitefully announces that his daughter is already Nevers' wife. The newlywed arrives with friends, and the grand procession, including the queen, heads to the wedding feast.
Act IV
In Count de Nevers' castle, Valentina seeks solace and renunciation of her love for Raoul through prayer. Unexpectedly, Raoul himself appears, seeking her forgiveness before he departs.
Footsteps are heard. Valentina urges Raoul to hide, and he conceals himself behind a tapestry. Saint-Bris, Nevers, and other Catholic nobles enter. Saint-Bris declares that, by the will of King Charles IX and the Queen Mother – Catherine de Medici, the time has come for a bloody reckoning with the Huguenot enemies. All swear readiness to exterminate the "criminal tribe of Huguenots," except Nevers, who refuses to become a murderer. Commanding his son-in-law's arrest, Saint-Bris reveals the conspiracy's plan to his followers, instructing them to begin the wholesale slaughter of Huguenots at the first bell of Saint-Germain-l'Auxerrois Church. They must first kill Admiral de Coligny, then proceed to the Nel mansion, where Marguerite and Henry of Navarre's wedding celebration is underway, and continue the massacre. The Catholics will be identified by white scarves.
Monks appear, blessing the conspirators and consecrating their daggers. The massacre is scheduled to start at midnight. The conspirators disperse. Raoul, an involuntary witness to the conspiracy, rushes to warn his fellow Huguenots of the impending danger. Desperate to keep Raoul and save him from certain death, Valentina confesses her love. Overjoyed, Raoul is momentarily distracted until the bell tolls, snapping him back to reality. Fires blaze outside the windows. Torn between his duty to his coreligionists and his love for Valentina, he pushes his beloved away in despair and rushes into the street to join the battling Huguenots.
Act V
Scene One
In the Nelle mansion, a ball celebrates the royal marriage. The dancing is interrupted by an alarm bell, with the sound of bells growing louder. Raoul bursts in, reporting the monstrous murder of Admiral de Coligny and calling the Huguenots to vengeance.
Scene Two
Marcel leads the Huguenots – women and children – to a cemetery chapel, seeking refuge from Catholic persecution. Valentina still hopes to save her beloved. With a white scarf on his arm, he could reach the Louvre, where the queen's protection would secure his life. Since Nevers has been killed as a traitor, Valentina could become Raoul's wife. But for that, the Huguenot must convert to Catholicism. Raoul, however, rejects this plan, unwilling to betray his co-religionists. Valentina decides to become a Protestant herself and share her beloved's fate. She asks Marcel to bless her union with Raoul. A group of Catholics appears, demanding the "apostates" renounce their "heresy," but they continue singing their hymn. The Catholics shoot the unarmed group. Silence falls. Marcel experiences a mystical vision: angels leading the martyrs to God. Disconnected from reality, Raoul, Valentina, and Marcel ecstatically embrace death. The killers again offer them Catholic conversion, but they bravely refuse. Saint-Bris orders them shot. Marcel and Raoul fall dead. To his horror, Saint-Bris recognizes his own daughter in the dying girl. Valentina promises to pray for her father in heaven.
