The Stepmother, Orange Tree Theatre

When's the last time you encountered a play with a hissable anti-hero and a young heroine who radiates charity, decency, and all things good? Those polarities are on full-throttle view in The Stepmother, the all-but-unknown Githa Sowerby play from 1924 that makes up in its vigorous appeal to the jugular what it may lack in dimension and subtlety (Chekhov this ain't.) And if the opening night is any gauge, Sowerby's tale of a young wife and her unctuous, much older rapscallion of a husband has a demonstrable capacity for evoking responses from the crowd. Panto season aside, I haven't heard this much audible squawking from the house in years.

Collectors of dramatic curiosities will flock to this as they are to the Finborough's somewhat comparable London Wall, though that later play remains the superior text. Both productions have much to say about the role of women in English society of a bygone age, and they share a focus on orphaned heroines who come unexpectedly into money. That said, John Van Druten's saga of office life in a City law firm offers no one on a par with The Stepmother's all but moustache-twirling paterfamilias, Eustace Gayden (Christopher Ravenscroft, pictured below with Julia Watson), when it comes to stage villains you love to hate.   

A widower with two daughters and never enough cash, Eustace sees a financial opportunity in the penniless teenager who had been caring for his recently dead sister and who against expectation has been named the beneficiary of the late Fanny's small fortune. Does 19-year-old Lois Relph (Katie McGuinness, pictured below) know what to do with this inheritance from her erstwhile employer? Eustace will tend to that, thank you very much, which he accomplishes by marrying this guileless and trusting young soul and obtaining power of attorney over her dosh. After all, or so he reasons, the money should have come to him in any case. 

What ensues owes not a little to Ibsen, not least as here presented in an astute Sam Walters production that visibly tightens the screws on all the characters. As was true of last year's much-acclaimed Young Vic revival of A Doll's House, one is always aware of dastardly behaviour rooted in economic need: money is the motivating factor here, and one can feel Eustace cracking under a financially needful weight that pushes him perilously close to domestic violence. Robyn Wilson's immaculately tailored suits are no guarantee of civility from the people wearing them.

The psychology, such as it is, extends to Sowerby subverting expectations prompted by the title. Far from being the wicked stepmother of lore, Lois in fact becomes an advocate and ally for Eustace's two daughters, who are of course far closer in age to her than she is to her husband. And in trying to facilitate the marriage of the lovesick Monica to the "rather decent" Cyril (Alan Morrissey), Lois is allowing the younger woman the satisfying partnership that has been denied to her.Lois does have a more well-intentioned suitor in the dashing form of Peter Holland (Christopher Naylor), though he, too, has his limits when it comes to commerce. A swirl of secrets and lies carries through to an ending that gives the plucky Lois pride of place, even if its specific mode of expression - the serving of tea - is every bit as English as Sowerby's penchant for using the adjective "queer" as it if were going out of style.

Best known for her earlier, barnstorming success Rutherford and Son (a one-time Katie Mitchell venture to be revived imminently by Jonathan Miller), Sowerby never saw The Stepmother professionally performed, and the piece remains more interesting for its content than for anything about the language itself (a lot of the writing comes from the "it can't be, can it" school of cod-melodrama). It's heartening to see a play in which virtue and generosity are seen to prevail, and if those qualities here apply more to women than to men, well, the blokes on this evidence don't deserve a cuppa.

• The Stepmother at the Orange Tree until 9 March