Halcyon Days, Riverside Studios, London

The publicity for this English premiere of Shoji Kokami's play promises an examination of "the cult popularity of suicide websites in contemporary Japanese culture". But though it was written, in 2004, in response to a spate of web-connected teenage suicides, the piece furnishes few insights into those morbid internet forums which encourage the lonely and depressed to form suicide pacts with strangers.

The three characters who want to end it all may have met online, but once the play has brought them together in the flesh it largely abandons its professed theme in favour of a clumsy, tiresome attempt to merge melancholy and madcap comedy. Gamely performed by a fine English cast in Kokami's awkward production, Halcyon Days falls back on the formula the author used in Trance, his play about social alienation and unstable identity seen at the Bush a few years ago.

The drag queen, the female psychiatrist and the journalist who imagines he is the Emperor of Japan in the earlier drama resurface as types here in Mark Rawlings's flamboyantly camp businessman (nicknamed "Hello Kitty"); Abigail Boyd's haunted Kazumi, a school counsellor stalked by the vengeful spirit of Akio (an eye-catchingly sarky and baleful Joe Morrow), a sixth former she let down; and Dan Ford's impressively intense Masa.

There are plays that intensify our sense of the mental anguish of would-be suicides through riotous laughter. One thinks of Alan Ayckbourn's Absurd Person Singular, where the depressed housewife's bids are farcically foiled by the inattentiveness in others that has driven her to make them. Not here, though. Humouring Masa's fantasy that they have signed to be human shields, to protect a local nursery, the other three characters agree to rehearse a version of a Japanese fairy-tale, The Red Ogre and the Blue Ogre, to present to the children.

It makes for an over-extended Pyramus and Thisbe-like romp, with Rawling's Kitty outdoing Bottom in attention-seeking eagerness. But the attempts to interpret this story in light of the characters' difficulties feel strained and the redemptive lunar imagery is as heavy-handed as the larkiness and lavatory jokes. Long before the end, this reviewer was losing the will to live.

To 18 September (020 8237 1111)