Master Lovewit leaves the city because of plague. His butler, Jeremy, known as Face to his friends of the underworld, invites Subtle, a swindler posing as an alchemist, and Dol Common, a prostitute, to join him in using the house as a base of operations for their rascally activities. Matters fare well for the three until a dispute arises between Face and Subtle over authority. Dol, seeing their moneymaking projects doomed if this strife continues, rebukes the two men and cajoles them back to their senses.
No sooner have Face and Subtle become reconciled than Dapper, a gullible lawyer’s clerk given to gambling, calls, by previous arrangement with Face. Dapper wants to learn from the eminent astrologer, Doctor Subtle, how to win at all games of chance. In the hands of the two merciless rascals, Dapper is relieved of all his ready cash, in return for which Subtle predicts that Dapper will have good luck at the gaming tables. In order to gull Dapper further, Subtle tells him to return later to confer with the Queen of Fairy, a mysterious benefactress who can promote Dapper’s worldly success.
Abel Drugger, an ambitious young druggist who was led on by Face, is the next victim to enter the house. To his delight, he learns from Subtle, who speaks mostly in incomprehensible pharmaceutical and astrological jargon, that he will have a rich future.
Next arrives Sir Epicure Mammon, a greedy and lecherous knight, with his friend Pertinax Surly, a man versed in the ways of London confidence men. Having been promised the philosopher’s stone by Subtle, Mammon has wild visions of transforming all of his possessions into gold and silver, but he is completely taken in by the duplicities of Subtle and Face. Subtle further arouses Mammon’s greed by describing at length, in the pseudoscientific gibberish of the alchemist-confidence man, the processes that led to his approximate achievement of the mythical philosopher’s stone. Surly, quick to see what is afoot, scoffs at Subtle and at the folly of Mammon.
During the interview, Dol appears inadvertently. Mammon catches sight of her and is fascinated. Thinking quickly, Face tells Mammon that Dol is an aristocratic lady who, being mad, is under the care of Doctor Subtle but who, in her moments of sanity, is most affable. Before he leaves the house, Mammon promises to send to the unprincipled Subtle certain of his household objects of base metal for the purpose of having them transmuted into gold.
The parade of victims continues. Elder Ananias of the Amsterdam community of extreme Protestants comes to negotiate for his group with Subtle for the philosopher’s stone. Subtle, with Face as his assistant, repeats his extravagant jargon to the impressionable Ananias, who, in his greed, declares that the brethren are impatient with the slowness of the experiment. Subtle, feigning professional indignation, frightens Ananias with a threat to put out forever his alchemist’s fire.
Drugger reappears to be duped further. Subtle and Face are delighted when he tells them that a wealthy young widow took lodgings near his, and that her brother, recently come into an inheritance, journeyed to London to learn how to quarrel in rakish fashion. The two knaves plot eagerly to get brother and sister into their clutches.
Ananias returns with his pastor, Tribulation Wholesome. The Puritans manage to wink at moral considerations as Subtle glowingly describes the near completion of the philosopher’s stone. Prepared to go to any ends to procure the stone, Ananias and Tribulation contract to purchase Mammon’s household articles, which, Subtle explains, he needs for the experiment; the proceeds of the sale will go toward the care of orphans for whom Subtle says he is responsible.
Subtle and Face also plot to sell these same household articles to the young widow, who, having just moved to London, is probably in need of such items. In the meantime, Face meets in the streets a Spanish don—Surly in clever disguise—who expresses a desire to confer with Subtle on matters of business and health.
Dapper returns to meet the Queen of Fairy. At the same time, Drugger brings to the house Master Kastril, the angry young man who wants to learn to quarrel. Kastril is completely taken in. Subtle, promising to make him a perfect London gallant, arranges to have him instructed by Face, who poses as a city captain. Kastril is so pleased with his new acquaintances that he sends Drugger to bring his sister to the house.
Kastril having departed, Dol, Subtle, and Face relieve Dapper of all of his money in a ridiculous ritual in which Dapper is to see and talk to the Queen of Fairy. During the shameless proceedings, Mammon knocks. Dapper, who was blindfolded, is gagged and hastily put into a water closet at the rear of the house. Mammon enters and begins to woo Dol, whom he believes to be a distracted aristocrat. Face and Subtle, in order to have the front part of the house clear for further swindles, shunts the amorous pair to another part of the house.
Young Kastril returns with his widowed sister, Dame Pliant; both are deeply impressed by Subtle’s manner and rhetoric. When the Spanish don arrives, Subtle escorts Kastril and Dame Pliant to inspect his laboratory. By that time, both Subtle and Face are determined to wed Dame Pliant. Face introduces the Spaniard to Dame Pliant, who, in spite of her objections to Spaniards in general, consents to walk in the garden with the don.
In another part of the house, Dol assumes the manner of madness. Subtle, discovering the distraught Mammon with her, declares that Mammon’s moral laxity will surely delay completion of the philosopher’s stone. Following a loud explosion, Face reports that the laboratory is a shambles. Mammon despondently leaves the house, and Subtle simulates a fainting spell.
In the garden, Surly reveals his true identity to Dame Pliant and warns the young widow against the swindlers. When, as Surly, he confronts the two rogues, Face, in desperation, tells Kastril that Surly is an impostor who is trying to steal Dame Pliant away. Drugger enters and, being Face’s creature, insists that he knows Surly to be a scoundrel. Ananias comes to the house and all but wrecks Subtle’s plot by talking indiscreetly of making counterfeit money. Unable to cope with the wily rascals, Surly departs, followed by Kastril.
Glad to be rid of his callers, Subtle places Dame Pliant in Dol’s care. They are thrown once more into confusion when Lovewit, owner of the house, makes an untimely appearance. Face, quickly reverting to his normal role of Jeremy, the butler, goes to the door in an attempt to detain his master long enough to permit Subtle and Dol to escape.
Although warned by his butler that the house is infested, Lovewit suspects that something is amiss when Mammon and Surly return to expose Subtle and Face. Kastril, Ananias, and Tribulation confirm their account. Dapper, having managed to get rid of his gag, cries out inside the house. Deciding that honesty is the only policy, Face confesses everything to his master and promises to provide him with a wealthy young widow as his wife, if Lovewit will have mercy on his servant.
In the house, meanwhile, Subtle concludes the gulling of Dapper and sends the young clerk on his way, filled with the belief that he will win at all games of chance. Subtle and Dol then try to abscond with the threesome’s loot, but Face, back in Lovewit’s good graces, thwarts them in their attempt. They are forced to escape empty-handed by the back gate.
Lovewit wins the hand of Dame Pliant and, in his good humor, forgives his crafty butler. When those who have been swindled demand retribution, they are finally convinced that they have been defrauded as a result of their own selfishness and greed.