The action of the play takes place on two levels. The main plot unfolds in the polite world; a parallel minor action occurs among the vulgar characters of the play. Scene 2 introduces the reader to two of the low characters, Mistress Overdone and Pompey. Claudio is another character of the main action, on a level with Angelo, the duke, and Escalus. Lucio serves as a sort of go-between, a gentleman born to the polite world, whose lifestyle and activities have led him into an acquaintance with the vulgar. Pompey and Mistress Overdone, as well as the "two Gentlemen," speak entirely in prose, while Claudio's lines are delivered exclusively in poetry. Lucio alternates between prose and poetry, depending upon the seriousness of his tone and the persons with whom he is speaking. Shakespeare sets off the two levels of action by this distinction of poetry from prose.
The action of the low plot parallels that of the main. The characters of both are suffering from Angelo's sudden enforcement of the city's morality laws. Claudio is to lose his life, Mistress Overdone her livelihood. The subplot also offers humor to provide a contrast to, and relief from, the tragic vein of the main plot. Lucio, the two gentlemen, Mistress Overdone, and Pompey exchange witticisms loaded with puns and word plays in the true Shakespearean style.
The repetition of the story of Claudio's arrest and the failure of Mistress Overdone and Lucio to acknowledge it, although they are clearly aware of it, indicate that some revision may have taken place, confusing the issue. It is also possible, however, that Shakespeare used this posture of ignorance to allow for additional witticisms on sex.
