The Weir, Royal Court, London

So Conor McPherson can't write dialogue? That was the opinion of certain critics after his last effort, St Nicholas. A story about south London vampires, recounted by a raddled Dublin theatre reviewer, it confirmed McPherson's reputation as Ireland's greatest living monologist. But was it a play? Well, The Weir is. And judging by Ian Rickson's impeccably acted, faultlessly directed production for the Royal Court Theatre Upstairs at the Ambassadors, it's a very fine one too.

Fans of McPherson will be glad to know that he hasn't lost his fondness for an old-fashioned yarn. Set in a peat-smoky pub in rural Ireland - the kind of den that hasn't seen a woman since the tourists left last autumn - The Weir revolves around five tales told by drinkers. In fact, the play is a story about the uses of stories: to charm against evil, defuse arguments, and say what can't be said in any other context.

A mist of loneliness hangs over the men in The Weir. There's Brendan, the thirtysomething bar-owner, almost resigned to singledom. Jack, a white- haired, besuited mechanic, can't disguise shyness with garrulousness. His assistant Jimmy lives at home with his elderly, ailing mother. Finbar (a small-time wheeler-dealer) brings to the bar a young Dubliner called Valerie, who has just bought a house in the area. He might as well have brought a Martian. The men are soon trying to impress her with ghost stories.

Each narrative reveals something concealed by the men's repartee. Only, for example, in his story about a spook on the stairs can the flashy Finbar admit fear: "I was like a boy, you know." When Jimmy recounts a spectral encounter with a child-molester, you wonder whether this is a distorted image of his own repressed sexuality. But Valerie's own narrative trumps all-comers: still a horror story in form, it's shocking because it's so personal. Valerie's ghost, her child, contacted her on the phone.

Julia Ford's dazzling, impassioned monologue leaves the audience in no doubt that Valerie's sorrow is genuine. Yet there's the smallest of hints that she may have turned a domestic tragedy into a ghost story as the only way of putting a public face on grief. The irony of her tale is that it sends the men - who've been glorying in spooky yarns - scuttling for rational explanations. Perhaps the phone-call was a crossed line. Or a hallucination.

The final tale - told by Jack - is the only one to shun the supernatural. It's the play's most moving passage, a tale of lost love. Unadorned and heartfelt, it feels like an emotional breakthrough. That said, it's not what anyone would call a resolution. For, unlike St Nicholas, The Weir isn't a linear story. It moves in circles, its narratives striking against one another, creating flashes of insight that give way to shadowy puzzlement. It's the kind of work that grows on second viewing - hard as it may be to imagine a better evening in the theatre.

To 26 July. Booking: 0171-565 5000 Adrian Turpin