In general outline, this play follows Latin models quite closely. In the main plot, a gentleman named Kno'well, concerned for his son's moral development, attempts to spy on his son, a typical city gallant; however, his espionage is continually subverted by the servant, Brainworm, whom he employs for this purpose. These types are clearly slightly Anglicized versions of ancient types of Greek New Comedy, namely the senex, the son, and the slave. In the subplot, a merchant named Kitely suffers intense jealousy, fearing that his wife is cuckolding him with some of the wastrels brought to his home by his brother-in-law, Wellbred. The characters of these two plots are surrounded by various "humorous" characters, all in familiar English types: the irascible soldier, country gull, pretentious pot-poets, surly water-bearer, and avuncular judge all make an appearance. The play works through a series of complications which culminate when the justice, Clement, hears and decides all of the characters' various grievances, exposing each of them as based in humour, misperception, or deceit.
The details of the plot, are, however, less important than the style of the play. Jonson's purpose is delineated in the prologue he wrote for the folio version. These lines, which have justly been taken as applying to Jonson's comic theory in general, are especially appropriate to this play. He promises to present "deeds, and language, such as men do use:/ And persons, such as comedy would choose,/ When she would show an Image of the times,/ And sport with human follies, not with crimes." The play follows out this implicit rejection of the romantic comedy of his peers. It sticks quite carefully to the Aristotelian unities; the plot is a tightly woven mesh of act and reaction; the scenes a genial collection of depictions of everyday life in a large Renaissance city.