The play begins with a prologue setting out the playwright’s aims. Firstly, Jonson seeks to give an accurate depiction of the “deeds and language” of Elizabethan London. Secondly, he wants to fill the play with characters that “show an image of the times.” If the play can achieve this portrait of “popular errors,” the audience will laugh at them and agree “there’s hope left” that they “may like men.”
Act One begins with Old Knowell asking Brainworm, his servant, to call his son, Edward. Old Knowell is happy that Edward seems to be enjoying his studies, but worried that he is too preoccupied with “idle poetry.” Knowell’s nephew, Master Stephen, comes by and asks Knowell if Edward has any books on hawking and hunting, to which Knowell chastises his nephew for being “wasteful.” A servant brings a letter intended for Edward, but Old Knowell decides to read it secretly first. It is an invitation from a roguish London gallant, Wellbred, bidding Edward to come and spend time in the Old Jewry and generally make mischief. Its tone offends Knowell; this prompts him to worry about the company his son keeps and consider whether he should actively intervene. Brainworm then delivers the letter to Edward and, instead of hiding the fact that Old Knowell has read it, tells Edward right away. Edward is delighted by the letter and plans to meet Wellbred later with Stephen in tow. Elsewhere in the city, the buffoonish townsman, Master Matthew, calls on Captain Bogadil, a braggart soldier. Bogadil is lodging at the house of Cob, a lower-class water-carrier. Matthew quotes pretentiously from Thomas Kyd’s Spanish Tragedy and complains that Downright, Wellbred’s half-brother, recently insulted his fashion sense. Bobadil shows him some sword-fighting techniques in an effort to prepare Matthew for any future altercation.
Act Two begins at the house of Kitely, a London cloth merchant. Kitely complains to Downright about the behavior of Wellbred, who has been lodging with him. According to Kitely, Wellbred has been keeping bad company and filling his house with “lascivious jests.” Matthew and Bobadil come by, looking for Wellbred; they leave soon after learning that he isn’t there. Downright gets increasingly angry about Wellbred’s reported behavior and finds Matthew and Bobadil highly irritating. As Cob comes by to deliver water, Kitely begins to worry that he is being cuckolded. When Dame Kitely and his sister, Mistress Bridget, show up, he pretends that his distress is due to a fever.
On London’s Moorfields, Brainworm enters disguised as a vagrant ex-soldier. He plans to follow Old Knowell, who is intending to spy on Edward, and relay any information he gleans back to the latter. When Edward and Stephen arrive, Brainworm stays in character and sells Stephen a sword. Stephen thinks his purchase is a good one, but in reality the sword is of poor quality. Soon after, Old Knowell comes by, wondering whether he ought to be intervening in Edward’s life or keeping his distance. Brainworm appears, still disguised, and begs for money from Old Knowell. Brainworm announces his name as Fitzsword. Old Knowell is disapproving, but agrees to take on Brainworm as a servant (not realizing the man he is talking already is his servant).
At the start of Act Three in a nearby tavern, Bobadil tries to complain to Wellbred about Downright but Wellbred refuses to hear anything bad said about his brother. Edward informs Wellbred about Old Knowell’s interception of the letter, and the two of them look forward amusedly to what might happen. They both mock Stephen, who insists on the extreme melancholy of his character without realizing he is the butt of the joke. Bobadil boasts about his previous war exploits and, taking a look at Stephen’s sword, informs him that he has been ripped off. Brainworm comes by; Wellbred and Edward laugh as Stephen tries to complain about his purchase. Brainworm reveals his true identity and informs Edward that his father is attempting to spy on him.
Meanwhile, Kitely’s jealousy and fear of being cuckolded are getting worse, so much so that he can’t concentrate on his business. Eventually he leaves to complete a transaction, instructing his servant, Cash, to report to him immediately if Wellbred and his entourage arrive at the house. Sure enough, the young gallants arrive soon. Wellbred and Edward praise Brainworm for his “absolute good jest.” Wellbred asks Cash if Kitely is inside; Cash lets slip that Kitely has gone to Justice Clement’s. Bobadil lights some tobacco, praising its quality ridiculously. Cob is offended by the smoke, causing Bobadil to beat him with a cudgel. Cash dispatches Cob to recall Kitely, who by now is at the house of Justice Clement, the local legal authority.
Receiving Cob’s message that Wellbred and his entourage have arrived at his house, Kitely rushes back in a fit of paranoid jealousy—despite Cob saying that he saw nothing untoward happening. Cob asks Justice Clement for an arrest warrant for Captain Bobadil, but, on hearing more about what happened, the judge comes close to imprisoning Cob for insulting tobacco.
Act Four starts back at Kitely’s house, where Downright chastises Dame Kitely for allowing Wellbred at the house; she protests that there’s very little she can do about it. Mistress Bridget (Kitely’s sister), Matthew, Bobadil, Wellbred, Stephen, Edward, and Brainworm all come in. Edward and Wellbred laugh as Matthew tries to woo Bridget with plagiarized lines of poetry. Downright enters in a fit of rage. When Wellbred describes Matthew’s behavior as “tricks” to Mistress Bridget, some of the characters take this as a sexual euphemism. Downright is especially irate and demands that Wellbred leave, taking his entourage with him. They draw their swords, but are split up by the others. Kitely arrives, prompting the others—apart from Downright—to exit. Downright vents his frustration; Bridget, Dame Kitely, and Kitely try to calm him down. By now, Kitely is certain that he has been cuckolded, thinking that Wellbred and the others are hiding in his house. He goes in to search for them.
At Cob’s house, Cob starts to suspect his wife, Tib, of cuckolding him. He orders her to stay inside and not admit any visitors, suspecting her of taking Bobadil as a lover. Meanwhile at the tavern, Edward and Wellbred instruct Brainworm to take a message for them. Wellbred announces his intention to help Edward marry Bridget.
Brainworm, still in disguise, finds Old Knowell again in a street in the Old Jewry; the latter man is with Roger Formal, Justice Clement’s assistant. Cunningly, he tells Old Knowell that Edward has discovered his father’s plans to spy on him; furthermore, he was involved in an altercation with Edward and his entourage earlier in the day. According to Brainworm (as Fitzsword), Edward can be found cavorting with “brave citizens’ wives” at the house of Cob. Formal wants to hear about Fitzsword’s life and goes out with him to drink wine.
Matthew, Edward, Bobadil and Stephen discuss Downright. Bobadil and Matthew promise to get back at him. Excited by this fighting talk, Bobadil brags once more about his heroic behaviors in battle, having seemingly been at all of the major ones of the previous years. Just then, Downright appears. He challenges Matthew and Bobadil, disarming the latter man with ease. Matthew runs away, leaving Bobadil to try and make excuses for his cowardly behavior. Stephen takes Downright’s discarded cloak.
Back at Kitely’s house, Wellbred explains Downright’s angry actions as merely being his nature. Brainworm arrives, now dressed as Roger Formal, and tells Kitely that Justice Clement has summoned him. Kitely frantically searches for Cash and Cob to act as “sentinels” while he is gone. Dame Kitely wonders why her husband is always searching for Cob; Wellbred craftily suggests that Cob’s wife, Tib, runs a brothel and facilitates Kitely’s adultery. In her own fit of jealousy, Dame Kitely grabs Thomas and heads for Cob’s house. Wellbred turns his attentions to Bridget, trying to persuade her to marry Edward. Kitely returns from Justice Clement—who hadn’t sent for him—and, on hearing that his wife has gone to Cob’s, rushes there too. In a London street, Matthew and Bobadil encounter Brainworm—who they think is Roger Formal—and ask him for a warrant for Downright’s arrest. In lieu of money, they give him jewelry and silk stockings. Brainworm tells the audience of his intentions to pawn these items to disguise himself as a “serjeant” to make the arrest.
Knowell arrives at Cob’s house, hoping to find Edward; Tib doesn’t know what he’s talking about. Kitely and Dame Kitely arrive, each thinking they will find the other in the act of adultery. Hearing of his wife’s alleged behavior, Cob beats Tib for her wrongdoing. They all resolve to go to Justice Clement to get his judgment on what has happened. Brainworm, disguised as a “serjeant,” encounters Matthew and Bobadil, who point them in the direction of Downright—except it’s actually Stephen, wearing Downright’s cloak. Downright does arrive soon, however, and agrees to be taken to Justice Clement, but only if Stephen goes too for stealing his coat.
Old Knowell, Kitely, Dame Kitely, Cash, Tib, and Cob assemble at the irreverent Justice Clement’s house. He quickly figures out that Knowell, Kitely, and Dame Kitely have been duped, pointing out that both Kitely and his wife got their information from Wellbred. Bobadil and Matthew arrive; Justice Clement is deeply unimpressed with the reports of Bobadil’s cowardice. Clement is surprised to see Downright arrive with Brainworm and Stephen, mocking Downright for agreeing to be arrested without seeing an official warrant. At this point, Brainworm comes clean about his exploits, and also informs the group that Edward and Bridget are getting married. Instead of being angry, Clement is impressed by Brainworm’s behavior, saying he deserves to “be pardoned for the wit o’ the offence.” Edward, Wellbred, Bridget, and Roger Formal arrive. Clement congratulates the newly-weds, and also mocks Matthew’s poetic pretenses. He orders there to be a “merry” feast to celebrate the marriage, and implores everyone to “put off all the discontent.” In high spirits, Clement talks about how the adventures of the day will be remembered and applauded for a long time into the future.