In a confrontation at the gates of the city, the duke reveals the truth and administers merciful justice to all.
Isabella accuses Angelo, but Mariana comes forward to claim that she was with him herself. The duke charges the two, along with Friar Peter, with being persuaded to their accusations by the absent Friar Lodowick (the duke). He leaves their case to Escalus and Angelo, exiting to return shortly, disguised again as a friar. Lucio accuses him of slanders against the duke and is helping to lead him off to prison when his hood comes off revealing the duke.
The duke then deals quickly with the cases at hand. He orders Angelo married at once to Mariana and then sentences him to death. Isabella pleads on his behalf, but the duke seems impervious. He has the provost bring out Claudio (his face covered) and Barnardine. The latter is pardoned, and when the former is revealed, the duke pardons both Angelo and Claudio. Threatening Lucio with whipping and hanging, the duke lets him off with marriage to the whore he has got with child. He promises a higher office to the provost for his services and tops off the scene by asking for Isabella's hand in marriage.
