The Duke is at a monastery, asking Friar Thomas to hide him there. He tells the friar that he has good reasons for hiding, and that he has lied to Angelo about his destination. The Duke explains that for the past fourteen years the laws have been flagrantly disobeyed, with little reproach from the government. As the Duke explains it, when the law only serves to threaten, because the lawmakers do not carry out the punishments dictated, the government loses its authority and "the baby beats the nurse" (I.iii.30). Since he gave the people liberties, he does not feel comfortable punishing them for them now, yet he worries about the state of affairs in Vienna. He asked Angelo to take over in order to act more strictly without reproach or hypocrisy. He wants to observe Angelo at work, and so he asks the Friar to provide him with a disguise which will make him look like a visiting Friar himself.
Meanwhile, Isabella is being introduced to the ways of the nunnery which she has decided to join. A man approaches, and the sister asks Isabella to answer the door, since she is not sworn in yet and therefore still allowed to speak to men. Isabella obeys and finds Lucio at the door, asking for her by name. Isabella asks him to explain what has happened, and he tells her that Claudio has impregnated his "friend." Isabella does not believe it at first and tells Lucio not to mock her. Lucio says that he is indeed telling the truth, and Isabella asks if the woman is her friend Juliet. When Lucio says yes, Isabella asks why they cannot simply marry. Lucio explains that the Duke is gone, and that the very logical and unemotional Angelo is serving as leader in his place. He also says that Angelo wants to make Claudio an example by executing him. Isabella asks how she can help, and Lucio says she should test whatever influence she has and visit Angelo, using her feminine charms and submissiveness to convince him to have mercy on her brother. Isabella says she will leave right away.Read a translation of Act I, Scenes iii-iv →
The Duke and Isabella are both described in more detail. They are both shown to be good-intentioned, sometimes confused characters who seek to improve the situation around them. The Duke wants to bring more law and order to Vienna but does not know how to do it himself, so he has allowed Angelo to take his place. However, he does not wish Angelo to have free reign, knowing him to be very strict and possibly heartless, so he asks Friar Thomas to disguise him so that he might roam the city in secret.
Isabella, similarly, seeks to retire from daily affairs. She joins a convent, thinking that she will find a safe, religious, pure environment in which she can worship. Her introduction to the life of a nun is interrupted by a plea from Lucio, and this is the first moment at which she must consider her choice. She is asked to leave the nunnery physically at this point; later she will be asked to give up her vow of chastity, and eventually she will be asked to marry instead of returning to the nunnery. Her physical departure is all the more important because she is asked to plead, on her brother's behalf, for forgiveness of what she and her religion consider to be a sin: fornication. At this point, she acts on familial loyalty rather than religious devotion, saying that she thinks the punishment for her brother's crime is warranted but too severe.
This first introduction to Isabella's beliefs about sexual behavior is particularly important. She will be asked to make major decisions and question her beliefs about acceptability and propriety, and her brother's life hangs in the balance. At this point, we see only that Isabella is innocent, chaste, and devoted to her religion. She is looking for protection from the sins of the common people of Vienna; Lucio brings her away from this safe haven into a situation in which she is vulnerable to the sins of others.