Act 1

Antonio Bologna, who has recently returned to Malfi from France, describes to his friend Delio the workings of the French court. The melancholy malcontent Daniel de Bosola enters and is spurned by his former employer, the Cardinal. After Ferdinand, the Cardinal’s brother, banters with the courtiers, Antonio delivers a speech of enthusiastic admiration in praise of the Duchess of Malfi, a young and attractive widow. The Duchess’s two brothers, Ferdinand and the Cardinal, both deliver a stern admonition to the Duchess of Malfi not to marry again, and Ferdinand engages Daniel de Bosola as his spy to monitor the Duchess’s marital status. The Duchess, however, soon reveals she is in love with Antonio, her steward. In defiance of her brothers’ orders, the couple celebrates a chamber wedding, with the maid Cariola as their witness.

Act 2

Nine months later, Daniel de Bosola arrives at the court with some apricots to test whether or not the Duchess of Malfi is pregnant. The Duchess experiences a sharp reaction to the fruit and withdraws. Antonio orders all the courtiers to remain in their own quarters, owing to a disturbance and theft at the palace. Cariola tells him the Duchess has given birth to a son. In semi-darkness, Bosola and Antonio Bolognia exchange aggressive insults. Departing, Antonio accidentally drops a piece of paper on which he has cast his newborn son’s horoscope. Retrieving it, Bosola vows to inform the Duchess’s brothers that Antonio is the child’s father. Meanwhile, in Rome, the Cardinal entertains his mistress Julia, who is the courtier Castruccio’s wife. The Cardinal and Ferdinand receive Bosola’s letter revealing the birth of a son to the Duchess, and Ferdinand explodes with rage.

Act 3

Two years have passed. Ferdinand proposes the Duchess of Malfi marry Count Malateste, but the Duchess dismisses this suggestion. Ferdinand then secures from Daniel de Bosola a skeleton key for the door of the Duchess’s bedchamber. In the following scene he covertly enters the chamber and threatens the Duchess. Agitated, the Duchess bids Antonio Bologna to flee to Ancona. To explain his sudden departure she fabricates a story that he has cheated on his accounts. Taking Bosola into her confidence, she confesses she has had three children with Antonio. He suggests she pretend she is going on a pilgrimage to the shrine at Loreto, located near Ancona. When she and the children arrive at Loreto, a dumb show, or pantomime, dramatizes the installation of the Cardinal as a military commander, as well as the banishment of Antonio, the Duchess, and their children by the state of Ancona—all arranged by the Cardinal. The Duchess and Antonio bid each other a sad farewell, with Antonio headed now to Milan. Bosola arrests the Duchess, who is now to be held in prison at her brothers’ orders.

Act 4

Angered by the Duchess of Malfi’s fortitude in prison, Ferdinand arranges to meet with her in total darkness, for he has sworn never to see her again. He presents her with a dead man’s hand, implying it is the limb of Antonio Bologna. Then Daniel de Bosola brings up the lights and draws back a curtain, revealing a collection of wax figures that simulate Antonio and the children in death. Ferdinand continues with his sadistic campaign to drive the Duchess to madness and despair. From the local hospital he assembles a group of madmen, who jabber at the Duchess but fail to drive her mad. Bosola now enters, disguised as an old tomb-maker. Accompanied by executioners, he orders the deaths of the Duchess, Cariola, and the Duchess’s children by strangling. Ferdinand enters to survey the slaughter. His bizarre reactions hint he is sliding into insanity. Meanwhile, Bosola experiences a wave of pity and remorse.

Act 5

The Cardinal uses his influence to strip Antonio Bologna of some of his land, and Antonio makes plans to confront the corrupt prelate, or church official. Meanwhile, Ferdinand has begun to suffer from lycanthropy, a disease that has him believing he is a wolf. The Cardinal pretends to Daniel de Bosola not to know about the Duchess of Malfi’s death. He commissions Bosola to track down Antonio in Milan and murder him. Julia and Bosola flirt with each other, but Julia, of whom the Cardinal has wearied, is soon disposed of when the Cardinal orders her to kiss a poisoned Bible. Near the Duchess’s grave, Antonio and Delio hear the ominous forebodings of an echo from a ghostly voice. In a fast-moving scene, full of confusion, Bosola accidentally stabs Antonio, whom he mistakes for the Cardinal. In the play’s final scene Bosola delivers death blows to the Cardinal and Ferdinand and is himself wounded mortally. In his dying speech he exclaims that mankind exists in a “deep pit of darkness.”