Grown-ups in wet nappies

But she should still turn down those high-voltage verbs and adjectives a few notches. Richard Greenberg's Three Days of Rain is enjoyable but not too original. You can rely on the characters, Manhattanites all, to find ways of dressing up potentially flat lines in ways that are wryly amusing, often self-consciously literary but seldom psychologically revealing: "He looks at me and sees something from Anaïs Nin, just because I'm gloomy", that sort of thing.

But Greenberg's play - which begins with Firth's edgy, embittered Walker Janeway returning from a year in hiding just too late for the funeral of the architect father he remembers as a big, silent blank - is hardly on that exalted level. I liked its wit and its sensitivity, but I fear that it will pretty soon join a dozen other diaper dramas in my private oubliette.

Act I presents us with the 1995 generation. Firth's Walker exudes tart self-pity. Morrissey overdoes the preening vanity of Pip, the actor son of Walker's father's partner and the man to whom Janeway Sr has controversially bequeathed his most famous building, and so has trouble convincing us of the modesty and decency that eventually characterise him. McGovern is effective enough as Walker's sister, a role that requires her to do little more than play the reconciler. They all make more of Act II, which takes us back to 1960, subverts Walker's theories about his father's inadequacies, and is, I suppose, a salutary reminder to kids not to categorise the old folk too glibly.

I shall reveal little more, for Greenberg has some nice twists in the offing. But Firth is touchingly truthful as an earnest stutterer with little self-belief and a terror of children, and McGovern unpretentiously excellent as a woman whose instability will, we know, destroy her. 

This is an actress who does more with her smile than most others with a score of gestures. On opening night, those curled lips expressed vulnerability, sensuality, mischief, diffidence, bewilderment, pain - in short, did everything but convince me that Rain really was an inspiring, vibrant play.

Three Days of Rain
Donmar Warehouse, London WC2

BENEDICT NIGHTINGALE © Copyright of The Times of London