The plot of Measure for Measure revolves around the difficulties that ensue when Duke Vincentio of Vienna retires, entrusting the responsability 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 controversial comic ending.