Timing is everything in David Ireland’s new play. Words that lie passively on the page can, and frequently do, elicit huge guffaws from the audience, thanks to their careful handling. Sean Gilder sets up the goals, Jack Lowden hits the back of the net, time and again. Until they don’t, but only because Ireland has taken us somewhere much darker.

A confusing chemistry hangs in the air between these two strong actors, and it’s not until the final scene that we understand why. Lowden plays Luka, a young man in need of an Alcoholics Anonymous sponsor who will help him steady his internal ship. Dressed in a t-shirt and trackie bottoms, a bundle of nervous energy, Luka is looking for love and understanding in all the wrong places. Gilder is his tranquil foil, James, a fatherly figure who looks like he’s got it all sorted, blanching slightly at Luka’s forthright descriptions of masturbation and sexual fantasy. 

Over 90 uninterrupted minutes, the two men keep our eyes glued to the stage. A mobile set takes us from community centre to cafe, gym to park bench, then starts to unravel structurally as their relationship slowly fragments. Ireland’s plot is littered with twists and turns, making us laugh knowingly at what we think we know, only to have our horizon-gazing disabused. Gilder is a dependable presence throughout, but to see Lowden (easily one of the finest actors of his generation) grasp this character with both hands is a rare privilege.

The Fifth Step, Lyceum Theatre, Edinburgh, until 25 August, times vary; Pavilion Theatre, Glasgow, 28–31 August, times vary; reviewed as part of Edinburgh International Festival.