Oran Mor, Glasgow

Mary Brennan

Four stars

At first, there’s a whiff of Arsenic and Old Lace in Ian Cowell’s first full-length play, Disturbed.

To an outside eye, Peter (George Drennan) and Grace (Anne Lacey) seem totally beige: an ageing married couple, drifting towards codgerdom in a safe routine of tea and biscuits, whisky (for him) and knitting (for her), with nothing but their sniping exchanges to alleviate the tedium.

Hah! they are in fact taking in boarders, systematically murdering them and burying them in the cellar. Grace has already advertised for a new victim.

This is where Cowell’s comic invention – abetted by Andy McGregor’s direction – nods enthusiastically in the direction of Joe Orton, and Disturbed acquires a lascivious nudge and a knowing wink with the arrival of an agreeably charming male lodger.

Grace is instantly smitten, as her eyes meet his over the sugar bowl – Matthew Tomlinson’s lodger is already oozing seductive sweetness, so much so that Grace doesn’t notice how manipulative he is.

Peter, who prides himself on being smarter than Grace – he can sometimes finish the Telegraph’s cryptic crossword – is so busy trying to impress this personable lad that he, too, falls for the flattery and sexually-loaded attention. The plot-twists hover on the predicable, not least because Cowell is happy to provide obvious clues, but subtle plotting is not the point here.

Instead, the emphasis is on the hugely entertaining dialogue that strips Peter and Grace down to their susceptibilities as Tomlinson woos and schmoozes them into a jealous rivalry for his favours.

Drennan and Lacey are simply a gift, here, shifting from initial prissiness into hot surges of unbuttoned desire with a consummate understanding of the facial expressions, body language, vocal inflections that deliver nifty shades of black to the comedy.