The Fortune Club, Tricycle Theatre, London

"Every time a friend succeeds," Gore Vidal wrote, "a little something inside me dies."

"Every time a friend succeeds," Gore Vidal wrote, "a little something inside me dies." Dolly Dhingra has been murdering little bits of former colleagues for a decade now: 10 years ago, she was a secretary on this paper's arts section, before striking out to become an award-winning freelance journalist and playwright (she is now playwright-in-residence at the Contact Theatre, Manchester). How could reviewing her latest play not be painful?

At the start of The Fortune Club, a group of thirtysomething friends have washed up in a run-down pub on New Year's Eve: Renu, a fluff-headed would-be actress, and her more mature, uptight sister, Priya, have spent their way out of a flat in Hampstead, north London. Priya's boyfriend, Gilly, a workaholic journalist, is overlooked by his editors. Tink wants to be a musician but is stuck as a traffic warden. Their Muslim friend Zaq is a genius, but feckless and unemployed. Mark is separated from his wife and child, largely because of rows about money.

Along comes Simmy, an old friend of Renu's, who has a well-paid but dull job looking after the accounts of high-profile clients at American Express. Zaq conceives a foolproof crime: with credit-card details supplied by Simmy, they can tag some inconspicuous spending on to large accounts - preferably celebrities, because it is easier to track their lifestyles and movements and hence to camouflage transactions. As long as their scam goes unnoticed, not only are they safe, but it remains in effect victimless. How can they resist the temptation?

Dhingra's writing has many strengths: an easy flow of naturalistic dialogue, an underlying sense of how to shape narrative, and a sense of humour. But the play doesn't hold together. Although it is "inspired by a true crime", the scam is thinly conceived - how do they convert their luxury goods into cash without drawing attention to themselves? Zaq reassures Simmy that, if they are caught, her name will be kept out of it. How? Why would she swallow such a flimsy promise? Without such details, it fails to satisfy on the level of the caper.

The characters are similarly short on plausible detail. Their various dilemmas are laid out rather too plainly, in dialogue that sometimes veers into the over-informative mode of TV soaps, and crucial plot-points are telegraphed in advance or jump out of nowhere. When Priya announces in the first scene that it has been three years and Gilly still hasn't told her that he loves her, the outlines of their subsequent row - her demands for commitment, his insistence that he does love her but... - are already visible, and nothing occurs to upset expectations.

In the second half, it emerges that Gilly's brother was murdered by racists while with Tink's brother: but with no lead-up or development, that simply feels like an extraneous attempt at tension. Despite the play's qualities and a production that makes the most of them, the plot never escapes cliché, and the characters don't break out of caricature. Oddly, I don't feel happy about saying that at all.

To 2 April (020-7328 1000)