The premise of Theatre West’s Picture This season is an engaging one: in April, 45 south west playwrights were each presented with a random photograph from a collection purchased at a Berlin marketplace and challenged to write a one act play inspired by the picture. Six months later, the first of the five successful plays, Steve Lambert’s The Darkroom, takes a very literal cue from its image – three chairs in a garden, two men, one woman.

Sadly, the obviousness of Lambert’s set-up doesn’t stop there: it’s 1949, and dark wartime secrets are threatening to invade the lives of a trio with plenty of skeletons rattling in their closets. Yet the writing lacks the subtlety necessary to pull off the attempts at tension-cranking plot twists, leaving discoveries intended to shock as tepid and predictable, whilst each of the three characters falls into the trap of cliché on an all-too-regular basis.

James, the socially awkward intellectual, Faye, the wife who just wants a normal life, and William, the sardonic toff, fail to break free of these roles, despite the inordinate amount of secrecy and controversy which surrounds their lives for the duration of the play. From a hammy, Dan Brown-esque piece of implausible code-cracking to an all too heavily signposted disclosure about James’ past, Lambert allows ‘revelations’ to cloud relationships – and director Pameli Benham doesn’t help the situation by piling on the visual clues. Most frustratingly, some of the less consciously provocative scenes are quite satisfyingly realised – if the fervent pursuit of a thrill factor could be quelled, the piece would almost undoubtedly improve.

The cast of Charlotte Ellis, Gerard Cooke and Duncan Bonner often seem distracted and introverted as a company, but all have strong moments as individuals. Notably, Ellis’ performance as Faye at the emotional climax of the piece, in Ruth Stringer’s well-designed darkroom of the title, is genuinely moving, and Cooke has a go at imbuing James with a nervous mix of inelegance and brains. But ultimately there is no escape from the clunky dialogue, which, on the whole, leaves The Darkroom as flat and lifeless as the picture it evolved from.

The Darkroom is playing at the Alma Tavern and Theatre until 15 October. For more information and tickets, see the website here.