Nightingale And Chase, Royal Court Upstairs, London

Nightingale fails to sing

The title may sound like that of a TV cop show, but it's only Nightingale who, in this two-character play, is the voice of authority. Both good and bad cop, he tries to subdue his own feelings – feelings he doesn't understand or feel comfortable with, while Chase runs riot with hers.

As in Zinnie Harris's previous play, the extraordinary Further than the Furthest Thing, the characters speak in isolation, haltingly, as if in the glare of an enormous microscope (effectively symbolised by Angela Davies' elegant set of curving white walls and a white floor with an exposed circle of parquet). Nightingale, a middle-aged working-class man, goes first. He tells us about bringing Chase home from an institution – we are unsure at first whether it is penal or psychiatric – where she has been for the past 10 months. He has carefully planned their evening – kid at his sister's, nice dinner, bottle of bubbly – but Chase won't play along. The reunion, edgy from the start, crumbles, then explodes. "In my head I am just watching her, calm, like my dad. But it isn't what my arms are doing, they are doing this other thing.''

Christopher Fulford portrays Nightingale with enormous sympathy for this man, who tries hard to live up to rules he but dimly comprehends, and who never ceases to be surprised when other people don't play fair. His body is stiff with propriety, his hands make little, aborted gestures. Chase runs off. The story continues with her monologue, describing her life in prison, where she was sent for fraud, and her equally dispiriting life with Nightingale, 20 years older, with whom she has lived since she was 16.

Despite Jody Watson's sensitive performance, showing up the character's vulnerable and appealing sides without softening her selfishness and manipulation, the play starts going wrong. In part, this results from the growing disparity between Harris's clinical style and Richard Wilson's taut production on the one hand, Chase's personality on the other. The restraint of the former, while suiting Nightingale, becomes an increasingly artificial device for exhibiting Chase's messy fractiousness. And while it's clear she has a couple of screws loose, Chase is much easier to sympathise with as a character in someone else's story, where we're not assaulted with her determinedly childlike behaviour, her narcissism masquerading as self-determination.

But the other, and greater, problem is that, finally, these characters and their actions are just not interesting enough to sustain a play, even one as slight as this, which, as it goes on, sounds more and more like a dramatised case study. One doesn't respond in a theatrical way but a therapeutic one -- ah yes, Nightingale is re-enacting his parents' marriage, Chase wants someone to look after her but resents him as an embodiment of her own weakness. The play's climax also rings false, depending on a dramatic police procedure which is very hard to believe. Harris is very good at creating her own world, but not when its probabilities run counter to our own.

To 27 Oct (020-7565 5100)