Small-town America, dysfunction and the murky underbelly of the American dream - we have, of course, been here before. It takes the finest of writers to cast this in a newly perceptive light, and Naomi Wallace is one such talent, weaving poetic symbolism into her tale to tell the story of Dalton Chance and Pace Creagan, two teenagers growing up in the Depression.
Theirs is a brutal landscape, emotional and physical, dominated by the trestle, the support structure for the railway bridge across which a huge steam train thunders every night. Unlike every other stagnant thing in their world, the train represents movement, adventure and the possibility of escape. But the escape is not going to come from hopping aboard: Dalton and Pace are caught up in a deadly fantasy of crossing the trestle as the train approaches. That this will never happen is underscored by Fiona Watt's bleakly minimalist set - the menacing trestle is like a gallows.
And hanging is the fate that awaits Dalton, who is accused of murdering Pace, found under the trestle, her dress stained with his semen. Wallace deftly and episodically reveals the dangerous games the two have indulged in under Pace's direction. Beautifully played by Julia Dalkin, Pace is the play's twisted spiritual core.
Everything beyond the two of them is blighted. Dalton's parents are caught in a spiral of despair - his father spends his days smashing plates and making animal shapes in shadows on the walls; his mother is ready to walk out. As she does, you see her hands are stained blue from the chemicals she works with at the factory. It looks as if she's wearing elegant light blue gloves.
In these details Wallace is a thrilling writer, handling the vilest emotional darkness with grace. As a portrayal of teenage angst and lust, this would be hard to better. But there is slightly too much in the way of symbolism in the second act - Dalton's jailer, whose own son died trying to do the trestle challenge with Pace, does animal shapes too, competing with Dalton's father when he comes visiting. Echoes of The Glass Menagerie are unavoidable, as these two inarticulate men silently make meaning with their hands.
This and the sexual symbolism of the steam train - rushing through the teenagers' lives as physical cravings do - are oddly heavy-handed moments in an otherwise spine-tingling performance, lightly done and terribly, horribly dark.
• Until March 18. Box office: 0131-228 1404.
