THEATRE / The cream in her coffee: Rhoda Koenig grapples with Obsession in Battersea

THEY MEET when he rings her bell one day and stays for a cup of coffee. She goes to his flat, he goes back to hers. They visit a gallery and giggle at what passes for art these days. She quizzes him about another woman, he is annoyed when she accepts another man's invitation for coffee at his place. 'You saved my life,' he says. 'You've ruined my life,' she says. He slams her head against the wall. With its short scenes that skip backward and forward through an adulterous affair, Obsession may aspire to comparison to Betrayal, but it's more like Further Adventures of the Gold Blend Couple.

Stripped of detail about their lives and backgrounds, Douglas McFerran's two characters are not only baffling but boring and, finally, incredible. We see Nick briefly messing about with a drawing and a T-square, so he must be an architect. But what is the work that keeps Nina busy on Saturday night, yet allows her to slope off for afternoons under the duvet? Considering the amount of time she spends in galleries, one assumes it has something to do with art, though her interest has a strong erotic focus. At an exhibition of the Vienna Decadents, she explains, 'The whole death imagery thing symbolises orgasm.' More recent imagery leaves Nina cold. When Nick suggests, at another show, that they make love on a soft sculpture, she says, 'I wouldn't dream of consecrating that heap of cowshit with the approbation of my sacred womanhood.' In the next-to-last scene, Nina reveals that she has become an art director at a publishing house and is producing a book on Kokoschka. 'He turns out to have been an extraordinary guy.' Not only did he have a mistress, but 'he was totally potty about her.'

Of Nina's family, we learn only that her husband is called Jack, and that her mother wanted her to be proper and would be shocked by all this rumpy-pumpy. Of Nick's life beyond the eiderdown, we learn nothing. Perhaps McFerran intended that, free of distracting personal information, his characters would represent pure, raw passion. But without those defining, colouring details, they are reduced to talking in cliches long abandoned by the more respectable women's magazines: 'I owe it to myself. I've got to try something else.'

In Bill Pryde's production at Battersea, as little heat as light is generated by Douglas Hodge's puppyish Nick and Tessa Peake- Jones's arch, domineering Nina. When Nick returns a tool he borrowed from her absent husband, Nina takes the opportunity to display her legs and offer one-and-a- half-entendre DIY advice about drilling deep and inserting rawl plugs. Nina's tough talk (after three years with him, she tells Nick, 'Let's face it, all I get from you is cock') doesn't go with her chatter about loving and being in love, nor does it discourage Nick, who, in their fourth year together, is begging her to marry him. Though Nick is younger and more pleasing than Nina, he doesn't outgrow his pottiness until she is unfaithful: supplied with a psychological CV, one might believe in his immaturity and masochism; without it, one can only find him a case of passive stupidity.

Just as we're stumped for an explanation of why the affair begins and carries on, we're not told why it vanishes without trace. Accidentally meeting Nick a few years after they part, Nina manages a fourth-form metaphor about a meteor: 'The tremendous white heat of its body has consumed it, until there's nothing left.' A better clue might be found in the final scene, in which Nina, at the height of her feeling for Nick, declares with thundering irony, 'We're going to love each other forever.' Disregarding the vital beverage of their relationship, Nick has poured her a cup of tea.

Battersea Arts Centre, London SW11 (071-223 2223)