- This scene opens with a bang: Vindice and Hippolito are holding their mother by the shoulders and threatening her with daggers. And this is the good family in the play. Yikes.
- They accuse their mother of being a bawd, someone who makes arrangements for prostitution in order to earn money. The mother is appalled, shouting, "A bawd? O name far loathsomer than hell!" (4.4.14)
- The brothers ask their mother if she agreed to help Lussurioso seduce Castiza, and she flatly denies it.
- Vindice reveals that he was the man Lussurioso sent, so he knows what his mother said.
- Their mother pleads for forgiveness and begins to cry, and her sons relent. A long philosophical conversation follows. That's revenge tragedy, all right—daggers one minute, philosophy the next.
- Vindice and Hippolito leave, asking their mother to give virtuous greetings to their sister.
- Castiza comes in and announces that her mother's previous arguments have convinced her, and she will sleep with the Duke's son for money after all. Has her mother repented too late?
- More long philosophical discussion follows, with Castiza repeating her mother's previous arguments for prostitution and her mother trying to talk her out of it. Finally Castiza admits that she's not planning to sleep with the Duke's son—she just did all this to test her mother. Golly. There's a lot of testing going around.
- The scene ends with the Mother and Castiza both happy that they've come round to agreeing with each other and living virtuously. Hurrah.