- Back at court, Vindice and Hippolito are disguising the corpse of the Duke. Hope they remembered the fake mustache.
- Vindice asks if Lussurioso is coming alone to the place where the body of the Duke is, and Hippolito says that he isn't. Vindice mourns the missed opportunity to kill Lussurioso after showing him the corpse of his father, but Hippolito assures him that there's likely to be another chance at it.
- Lussurioso turns up. When he sees the body of his father in Piato's clothes, he thinks it's Piato, still alive.
- Vindice asks if they should kill Piato while he's drunk, and Lussurioso says that's best of all (5.1.51). Vindice asks if Piato will never live to be sober then, and Lussurioso says it won't matter and Piato can go to hell. This isn't just strong language: Lussurioso actually means it. Since many people in the time period believed that those who died repentant found God's mercy and those who didn't went to hell, Lussurioso is showing his callousness toward Piato's eternal destiny.
- Egged on by Lussurioso, Vindice stabs the corpse of the Duke (disguised as Piato).
- Lussurioso realizes that the body is that of his father, and cries out that Vindice and Hippolito are villains and murderers; Vindice whispers to the audience that it's a jest or joke (5.1.71).
- Then Lussurioso realizes that the corpse was already dead, and he concludes that Piato must have murdered his father and then left. He decides to show the scene to the whole court, including the Duchess, Spurio, and everyone else.
- Vindice has an aside saying how well all his plans are working out. Lussurioso goes all CSI, though, and realizes that his father was poisoned by looking at his damaged lips. Did we mention forensic knowledge wasn't so advanced at this time? Because it wasn't.
- The court turns up. Unsurprisingly, Supervacuo and Ambitioso pretend to be sad while whispering to each other about how glad they are that they're closer to becoming dukes through their stepfather's death. Spurio doesn't sound too sad, either.
- Lussurioso, meanwhile, is continuing to investigate the mystery—he's really angling to replace Benedict Cumberbatch as Sherlock next season—and he asks which lords said the Duke had ridden out privately. One gentleman admits that the Duke insisted they say that, but he was actually in a private meeting with Piato. Lussurioso is angry with the gentleman and sentences him to death. Seems a little extreme for just doing what the Duke told him to do.
- Lussurioso sends a posse out in all directions to find the guy who killed the Duke, while Vindice and Hippolito laugh up their sleeves.
- Someone points out that Lussurioso is now the Duke. He says he's too busy mourning his father to think about that, but secretly chuckles about how happy he is to be inheriting the title.
- The noblemen plan the funeral, as well as revels (celebrations) for Lussurioso's becoming Duke.
- Lussurioso mutters to himself that the Duchess is suspected and decides to banish her at the beginning of his career as Duke.
- There's plenty of plotting to go around. Spurio seems to be planning a way to get the Dukedom, while Supervacuo and Ambitioso are planning to kill him during the masked ball to celebrate the new duke. Ambitioso is planning to murder Supervacuo after that, so he can be duke. Good times.