In a preface to the published play, the playwright addresses the critics who had found the previous performances obscene, claiming that was not his intention.

I am even to this Day insensible of those two shining Graces in the Play (which some part of the Town is pleas'd to compliment me with) Blasphemy and Bawdy. For my part, I cannot find them out: If there were any obscene Expressions upon the Stage, here they are in the Print

As the play opens, Loveless and his wife, Amanda, newlyweds living in rural England, are conversing. When he tells her he has to go up to London on business, she worries that he will cheat on her, because he had a bad reputation when she married him. He professes surprise:

Can you then doubt my Constancy, Amanda?

You’ll find ‘tis built upon a steady Basis—

The Rock of Reason now support my Love . . .

As they continue the discussion, he reproaches her again, with the line that explains the title, wondering that she “can believe 'tis possible / I shou'd again relapse to my past Follies.”

The action then turns to London, where the young Tom Fashion bemoans his impoverished state, and his servant, Lory, urges him to “wheedle” his vain, wealthy brother, Lord Foppington.

[A]pply yourself to his Favourites; speak to his Perriwig, his Cravat, his Feather, his Snuff-box, and when you are well with them—desire him to lend you a Thousand Pounds.

The plot complications now revolve around the lord’s desire to marry. Fashion decides to thwart these desires by pretending to be the lord and marrying the young woman himself.

Loveless gets to the city, and he sees a lovely woman at the theater. He makes the mistake of telling his wife, describing “the Face of a young Lady that sat some distance from me, she was so exquisitely handsome.” It turns out she is Amanda’s good friend Berinthia, and when they actually meet, he is immediately smitten with her. When Foppington comes to call, they all decide to make fun of the pretentious social climber.

Amanda: Now it moves my Pity more than my Mirth, to see a Man whom Nature has made no Fool, be so very industrious to pass for an Ass….

Berinthia: …[T]he Town wou'd be robb'd of one of its chiefest Diversions, if it shou'd become a Crime to laugh at a Fool.

Fashion’s plan advances, and he convinces Sir Tunbelly Clumsy that he should marry his daughter, Hoyden, right away. Meanwhile, Loveless and Berinthia start an affair, as her former lover, Worthy, makes advances toward Amanda. When Foppington arrives to arrange his marriage, his brother calls him an impostor and Sir Clumsy’s men detain him. Further complications ensue as Berinthia helps Worthy plan how to tempt Amanda into an affair while she carries on with Loveless. The mix-up with Fashion and Foppington is finally resolved, with Fashion married to Hoyden, while Foppington (who speaks in an affected tone) waxes philosophical about his loss.

I think the wisest thing a Man can do with an aking Heart, is to put on a serene Countenance; for a Philosaphical Air is the most becoming thing in the Warld to the Face of a Person of Quality . . .