A duke temporarily removes himself from governing his city-state, deputizing a member of his administration, Angelo, to enforce the laws more rigorously. Angelo chooses as his first victim Claudio, condemning him to death because he impregnated Juliet before their marriage.

Claudio's sister Isabella, who is entering a convent, pleads for her brother's life. Angelo attempts to extort sex from her, but Isabella preserves her chastity. The duke, in disguise, eavesdrops as she tells her brother about Angelo's behavior, then offers to ally himself with her against Angelo.

Modern responses to the play show how it can be transformed by its reception in present culture to evoke continuing fascination. To some, the duke (the government) seems meddlesome; to others, he is properly imposing moral standards. Angelo and Isabella's encounter exemplifies sexual harassment. Others see a woman's right to control her body in Isabella's choice between her virginity and her brother's life.