The plot of Measure for Measure revolves around the difficulties that ensue when Duke Vincentio of Vienna retires, entrusting the responsibility of government to his puritanical deputy Angelo. By strict enforcement of the law, Angelo sentences to death young Claudio who begs his chaste sister Isabella to intercede for him. Angelo falls in love with Isabella, and offers to spare Claudio's life if she will become his mistress. The scene is set for a play of disturbing moral choices.It is so dark a comedy that it is usually classed among Shakespeare's 'problem plays'. Dealing as it does with subjects as diverse as justice and mercy, morality and the law, lust and hypocrisy it is one of Shakespeare's most fascinating plays,but its powerful themes raise more enduring issues than can be resolved by the conventional comic ending.

Measure for Measure is formally a comedy but so dark in tone that it is more often neutrally classed among the "problem plays". It was first performed c. 1604 and published in the First Folio of 1623. The main source is George Whetstone"s Promos and Cassandra, a translation of a play by Cinthio.

Disturbed by the unruliness of Vienna, Duke Vincentio resolves to absent himself from rule and entrust law-enforcement to his puritanical deputy, Angelo. Disguised as a friar, the duke remains in Vienna to observe the consequences of his decision. Angelo orders the destruction of the brothels and, invoking a law against lechery,imprisons Claudio for impregnating the woman to whom he is betrothed. Knowing that the penalty is death, Claudio asks his sister, Isabella, a novice in a nunnery, to intercede. Confronted by Isabella, the unyielding Angelo experiences his own lust. He offers Claudio"s life as an exchange for Isabella"s body. Outraged when Claudio begs her to accept the offer, Isabella abandons him, but is persuaded by the disguised duke to play a trick on Angelo. The duke reveals that Angelo had broken a marriage-contract with a certain Mariana when Mariana"s dowry was lost. Mourning her lost love, Mariana now lives in isolation. She would willingly take Isabella"s place in Angelo"s bed. The substitution is arranged, but the duke"s scheme is ruined by Angelo"s decision to have Claudio killed despite his promise to Isabella. The fortunate death in prison of a pirate with some physical resemblance to Claudio gives the duke another opportunity to thwart Angelo, whose villainy is unmasked when the duke makes his unexpected "return" to Vienna.Claudio can now marry the pregnant Juliet. Angelo"s punishment is to marry Mariana, and the duke declares his love for the chaste Isabella.