Apologia, Bush Theatre, London

The lead character in Alexi Kaye Campbell's new play, Kristin, is a radical art historian with a startling resemblance to Elizabeth Frink. She's played by Paola Dionisotti with a throwaway bitchy style and a voice pitched somewhere between Maggie Smith and Sheila Hancock.

It's a heady concoction, this portrait of the artist as a bad mother, but it burns brightest, funnily enough, during a long speech about Giotto, whose humanism emerging from the religious matrix is all Kristin wants to know about Christianity. Her elder son, a banker, is about to marry a dim American chiropractor whom he met at a faith meeting.

Her second son, Simon, a failed novelist, arrives late for dinner bearing the weight of having been pushed out of his mother's life by her selfish 1960s political hedonism. Embittered by the fact that neither he nor his brother has been name-checked in mum's memoirs, he relates a tale of adolescent woe which implies he was scarred for life by a strange man in Genoa.

"Genoa? I've never even 'eard of 'er," would be the obvious reaction, perhaps, but instead mum kisses him lightly on the head and goes to bed, and the playwright saves the news of a domestic planning accident until the last scene. Dionisotti and John Light play it very well, but they're wrestling with demons that seem manufactured to make a rather unconvincing point about spiritual and social conditioning.

It's not easy to warm to Josie Rourke's production, which stutters under the weight of its own verbiage. We're huddled in the kitchen, where the oven conks out, a finger nail is seen floating in the takeaway and a bottle of red wine gets splashed over a designer dress.

Inside the dress is beautiful Nina Sosanya as Claire, an actress married to Simon. She's forsaken Ibsen in attic theatres to play in a television soap and is having hardcore sex outside the marriage. Her opposite exemplary number, the annoying American chiropractor, Trudi, is played with high decibel enthusiasm by Sarah Goldberg.

Trudi and Kristin come to some kind of post-feminist compromise. This is where the Liberian mask plays its part, but meaning has come unstuck from dramatic gesture. Dionisotti goes into tragic acting mode and silent screams us into submission. It's a good end, but I've no idea what it's meant to do to us.

To 18 July (020 8743 5050; www.bushtheatre.co.uk)