Towards the end of Lesley Bruce's play there are ten glorious minutes when the two male protagonists, like stags with antlers interlocked, engage in a male supremacy duel.

It starts when one of them - a bike-riding academic who is husband of the confused woman sitting on the airbed, but who has of late been somewhat liberally interpreting 'in statu pupilari' with a young student - quotes Sir Gawain and the Green Knight at some length in the original medieval English. His rival for the woman's affections responds with a battery of tongue-twisters; and from there it develops from backwards somersaults and cartwheels, through push-ups and squat-thrusts, to a Bob Fosse dance routine and an involuntary dive by the prof into a chest freezer. It is a most exhilarating sequence to which the audience rises enthusiastically.

It's worth dwelling upon that burst of frenetic energy because the rest of Bedtime Stories is pretty dire. It's not as if Bruce is a poor writer - she handles dialogue quite niftily, if not quite to a standard which would justify the "sparky comedy" label attached to this play; but she loses the plot in such big style that you're left wondering quite what director Laurie Sansom was doing throughout rehearsals.

It's as if the writer has been given a playwriting exercise and fluffed it: "You arrive home from your mother's funeral to discover that your bedsit has been taken over by a huge four-poster bed and that there's a complete stranger on it wearing your pink T-shirt, fun socks and Levi's. Find your way out of that."

What Bruce does is introduce multiple references to the moon - making it the anniversary of Neal Armstrong's "short step", apparently to justify backtracking the second act 33 years to the night of a moon-landing party. The bed, it transpires, is a bequest from Joni's recently late mother, which has miraculously skipped probate and arrived in her flat ahead of her after the funeral.

It also transpires that this is the bed on which Joni was conceived (though the flashback Act Two strongly and inexplicably suggests that this is impossible); and this simple news leads Joni herself to conceive the idea that she might like to conceive her own child right here and now with the stranger whom she'd never seen before 30 minutes ago. Enter, up a rope and through the window, an Australian on his way to a safari to spoil the coupling.

Battling very gamely to hold this crumbling edifice up, Sarah Moyle gives us a couple of splendidly kooky women in Joni and her mother Fran, though there are slightly worrying echoes of middle-period Bonnie Langford in the latter. The two blokes have a thinner time, but Will Barton as first the interloper and then the academic invests each with enjoyable idiosyncrasies and Pascal Langdale, given no chance with the Aussie, does at least excel in the ten-minute physical dash towards the end.

You'd need to travel far to find a slower, dafter play than this, and apart from the sequence of splendid mayhem, Scarborough's audience, longed weaned on far better comedies, sat rather quietly throughout.

- Ian Watson (reviewed at Scarborough's Stephen Joseph Theatre)