In the Cardinal and Ferdinand’s palace in Milan Pescara and a Doctor discuss the condition of the Duke. The doctor says that Ferdinand has the disease lycanthropia, which causes people to imagine that they are transformed into wolves and to dig up dead bodies at night. Ferdinand has apparently been seen with a dead man’s leg over his shoulder, howling and saying he was a wolf. Ferdinand apparently also said that the only difference between himself and a wolf was that his hair was on the inside instead of the outside, and that the people who spotted him should cut him up to see that he was telling the truth. Despite this, the doctor claims that the Duke seems to have recovered.
Ferdinand’s supposed lycanthropia echoes his comment that wolves would discover the Duchess’s grave; the condition is clearly driven by his maddening guilt. The image of him digging up actual dead bodies is another one of the play’s most gruesome moments. Ferdinand’s comment that the only difference between him and a wolf is fur on the inside seems to suggest he’s aware of the inversion of internal and external he’s been experiencing, and his inability to control what he outwardly projects.
However, the Doctor says that there is reason to anticipate a relapse. Therefore, he wants to try to cure Ferdinand of his madness altogether. Ferdinand, Malateste, the Cardinal, and Bosola then enter. Ferdinand begins acting insane, asking to be left alone and attacking his own shadow, which he says he hopes to carry to hell as a bribe. The Doctor confronts Ferdinand and asks him if he’s insane. The doctor says he will try “mad tricks” to heal Ferdinand, by which the doctor means he’ll act insane, too. Ferdinand says he’s afraid of the doctor and starts undressing, at which point the Cardinal restrains him. The doctor then instructs the Cardinal to let the Duke go, since he believes the Duke is afraid of him and will now act calmly. However, once the Cardinal lets Ferdinand go, Ferdinand attacks the doctor and leaves the room. The doctor then concedes that the cures weren’t exactly working.
It’s difficult to discern how much of Ferdinand’s madness is legitimate, how much of it is feigned, what is to be taken as horrifying, and what is just silly. After claims that he digs up dead bodies, he attacks his own shadow and starts getting naked on stage. The doctor, too, seems to encourage him with strange talk about nonsensical cures. All the while, in his madness, Ferdinand continues to express guilt and subtle hints towards what he’s done, causing the Cardinal to fear that Ferdinand will reveal the secret murder.
Standing aside from this spectacle, Bosola comments that a fatal judgment has fallen on Ferdinand. Meanwhile, Pescara asks the Cardinal if he knows what has caused Ferdinand’s outburst. The Cardinal lies and tells a story that an old woman who was murdered by her nephews haunted the Duke and sent him into this frenzy. Bosola then steps forward and says that he wants to talk to the Cardinal; everyone else exits.
Bosola reinforces the idea that in this life we experience judgment and punishment for our sins. It’s telling that the Cardinal’s fabricated story is one of familial betrayal, suggesting that his own guilt is growing—it’s just not yet consuming him as Ferdinand’s is.
The Cardinal says in an aside that he doesn’t want Bosola to know that he was an accessory to the Duchess’s murder. The Cardinal then asks Bosola how the Duchess is doing, pretending not to know that she is already dead. He tells Bosola not to worry about Ferdinand’s behavior. Julia briefly enters and asks the Cardinal if he is coming to supper. When he says that he’s busy, she departs, while remarking to herself how handsome Bosola is.
The Cardinal continues to be careful and calculating, hiding what he knows about the Duchess’s death and assuring Bosola that Ferdinand’s madness is nothing to worry about. Julia’s little aside proclaiming infatuation with Bosola continues to solidify her characterization as an inconstant, promiscuous woman.
The Cardinal then says that he has found the perfect man for the Duchess to marry, but he says that in order to make the match Bosola must first find Antonio and kill him. Bosola asks how he will find Antonio, to which the Cardinal responds that Bosola should follow Delio and possibly bribe him if necessary. After Bosola agrees, the Cardinal exits. Bosola then comments to himself that the Cardinal has nothing but murder in his eyes. Bosola notes that the Cardinal is pretending not to know about the Duchess’s death and he says he’ll have to be similarly cunning
The Cardinal continues in his lie and shows himself a corrupt mastermind. He is easily able to provide instructions for Bosola to find Antonio, and we can note that by this point in the play the Cardinal has completely abandoned his pretense of ignoring Bosola. Bosola notes that the Cardinal is also losing his ability to conceal his inner thoughts, as he sees nothing but murder in his eyes.
Just then, Julia reenters holding a pistol. She threatens Bosola and accuses him of giving her a love potion, as this is the only explanation she can think of for falling in love with him so quickly. He disarms her by embracing her and taking her gun, and she begins flattering him. Bosola says that he doesn’t have the skills to flatter women, but she says that ignorance in courtship (i.e., the inability to smooth-talk) won’t be a problem if his affections are genuine. He tells Julia that she is beautiful, and then realizes in an aside that he can use her against the Cardinal. He asks her if the Cardinal would be angry if he saw them together. She replies that the Cardinal would call her a wanton but would not get angry with Bosola. She tells Bosola to ask her to do something right away so that she can show him that she loves him, and he takes this opportunity to ask her to find out why the Cardinal has been melancholy lately. She agrees to be his spy, and has him hide inside a wardrobe.
This courtship scene is at once high-intensity and comedic. Bosola has thus far been uninterested in women, but here he seems taken with Julia, especially when he realizes that he can use her to get information out of the Cardinal. In another inversion of traditional courtship, she educates him on proper flirtation and flattery before he’s able to praise her. Given her stereotypical character, it’s unsurprising that Bosola doesn’t need to work hard to turn this new infatuation to his advantage; Julia almost immediately asks for some task to prove her love to Bosola, and the self-loathing spy recruits her as his own spy against the Cardinal.
The Cardinal then reenters the room, worrying to himself that Ferdinand in his insane state might talk about the murder. Julia asks the Cardinal what’s wrong, and he says nothing, but she continues to press. She asks why she can’t know his secrets, saying that she’s different than all of his flatterers. He tries to explain by having her imagine that he has committed some secret deed that he didn’t want anyone to know about, but she replies that the two of them have committed and concealed their adultery. He says that learning the secret will bring about her ruin and will act like a poison in her, but she continues to press until he tells her that the Duchess and two of her children have been strangled.
The Cardinal, too, seems to be unraveling, but when Julia presses he declines, at first, to confide in her. He echoes a sentiment expressed earlier in the play, that secrets are like dangerous poisons. It’s difficult for the Cardinal to justify keeping the new sin from Julia, though, because the two of them have already committed the secret sin of adultery together. He eventually tells her the truth, and he includes the vivid detail that they were strangled (when he could have just said killed), which possibly indicates a hidden desire to talk about the killing.
The Cardinal asks if Julia can keep this dark secret, but she says that he is in trouble, because she actually cannot keep it. He asks her to swear upon and kiss a book to show she will keep the secret. Once she does it, he announces that her curiosity has killed her, as he poisoned the book because he knew she couldn’t keep the secret. Bosola hastily emerges from the wardrobe in an attempt to stop the Cardinal, but too late. Julia says that she forgives the Cardinal for the “justice” he has done to her, because even as he did it she was betraying him to Bosola. She then dies.
Upon hearing the truth, Julia immediately knows she is incapable of keeping the secret, a final reinforcement of her inconstant character. After calling the secret a figurative poison, the Cardinal uses literal poison to kill Julia, which he apparently prepared because he knew that she would be unable to handle his secret. Julia reinforces the idea that punishments are generated by sins, as she admits to betraying the Cardinal to Bosola in her dying breath.
Bosola jumps out of the wardrobe and says that he has come to the Cardinal to try to collect payment for his service, since Ferdinand in his crazed state will not pay. The Cardinal threatens to hack Bosola to pieces and demands to know how Bosola got into the wardrobe. Bosola responds that it was all because of Julia’s lust. The Cardinal then confesses that he is Bosola’s fellow murderer, and says that he has wealth and other honors in store for Bosola. Bosola responds that there are many ways to get what seems like honor and some of them are horrible. The Cardinal tells Bosola to give up his melancholy air, and asks if Bosola will kill Antonio. Bosola says he will. The Cardinal then gives Bosola the master key to his lodgings and tells him to come that night to help remove Julia’s body.
Since he’s been unable to get the benefits he was promised from Ferdinand, Bosola tries to collect from the Cardinal. The Cardinal, though, is stunned and furious that Bosola has been hiding in his wardrobe, and he makes a violent threat reminiscent of Ferdinand’s. After confessing, the Cardinal promises Bosola he will finally get what he wants (wealth, honor, and status) if he agrees to kill Antonio. Bosola is weary of the actions that some take to gain honor, so the audience is not sure if Bosola agreeing to kill Antonio is genuine.
After the Cardinal exits, Bosola cries out that he pities Antonio. He ultimately decides to seek Antonio out and try to get him away from the brothers who have already spilled some of Antonio’s blood (in the form of Antonion’s family); Bosola even says that he might join Antonio in seeking revenge. Bosola comments that he thinks the Duchess is still haunting him, but quickly decides that in fact it is just his remorse.