Mercédès draws Monte Cristo away from the crowd and tries to coax him into eating some fruit from the garden. She becomes agitated when he refuses, perhaps because she knows that it is an Arabian custom that those who have eaten together beneath the same roof are eternal friends. Monte Cristo and Mercédès discuss their past in a roundabout way, never explicitly acknowledging that either is aware of the other’s old identity. Monte Cristo promises that he considers Mercédès a friend. Villefort appears in search of his wife and daughter, bearing the terrible news that his former father-in-law, the Marquis de Saint Méran, is dead.
That same night, the Marquise de Saint-Méran becomes sick, and the next morning she announces that she is going to die. She describes that during the night she saw a white figure approach her bed and heard it move the glass on her nightstand. The marquise yearns to see Valentine married before she dies and orders that the marriage contract be signed the day after Franz d’Epinay returns to France. Valentine longs to tell her grandmother that she loves another man but knows that her aristocratic grandmother would never allow her to marry a man from a family as common as Maximilian’s.
Valentine finds Maximilian waiting for her in the garden. He tells her that Franz has arrived in Paris and asks her to run away with him. After some coaxing, she agrees. That night, Maximilian waits for Valentine, armed with all they need for their escape, but she does not appear. Terrified that something has happened to her, he approaches the house and overhears a conversation between Villefort and a doctor. The marquise has died, and the doctor is convinced that she was poisoned with brucine.
The doctor suggests that the marquis and marquise might have accidentally been given a preparation intended for Noirtier, as Noirtier regularly takes brucine in small doses to alleviate his paralysis. Overcome with anxiety about Valentine’s well-being, Maximilian sneaks into the house and finds her. Valentine introduces Maximilian to her grandfather. Noirtier tells Maximilian that he has a secret plan to prevent Valentine from marrying Franz.
Immediately following the burial of the marquis and marquise, Franz d’Epinay comes to the Villefort home to sign the marriage contract. Just as they are about to sign, Barrois appears and says that Noirtier wishes to speak to Franz.
Noirtier instructs Barrois to open a secret compartment in his desk and to hand Franz a stack of papers. The papers reveal that Noirtier killed Franz’s father in a duel. Villefort flees in shock.